Low-density high-strength concrete and related methods

ABSTRACT

A low-density, high-strength concrete composition that is both self-compacting and lightweight, with a low weight-fraction of aggregate to total dry raw materials, and a highly-homogenous distribution of a non-absorptive and closed-cell lightweight aggregate such as glass microspheres or copolymer polymer beads or a combination thereof, and the steps of providing the composition or components. Lightweight concretes formed therefrom have low density, high strength-to-weight ratios, and high R-value. The concrete has strength similar to that ordinarily found in structural lightweight concrete but at an oven-dried density as low as 40 lbs./cu.ft. The concrete, at the density ordinarily found in structural lightweight concrete, has a higher strength and, at the strength ordinarily found in structural lightweight concrete, a lower density. Such strength-to-density ratios range approximately from above 30 cu.ft/sq.in. to above 110 cu.ft/sq.in., with a 28-day compressive strength ranging from about 3400 to 8000 psi.

RELATED APPLICATIONS

The present application claims priority to: U.S. Provisional ApplicationSer. No. 62/216,255, filed Sep. 9, 2015; to pending U.S. patentapplication Ser. No. 14/642,141, filed Mar. 9, 2015; and to pendingInternational Application No. PCT/US15/019510, filed Mar. 9, 2015. U.S.patent application Ser. No. 14/642,141 and International Application No.PCT/US15/019510 each claim priority to U.S. Provisional Application Ser.No. 61/950,202, filed Mar. 9, 2014. Each of these applications areincorporated by reference in their entirety.

FIELD OF INVENTION

In general, this invention relates to low-density, high-strengthconcrete that is lightweight, and to related concrete mixes that may beself-compacting and that, among the many multiple uses thereof, may beused for walls, building structures, architectural panels, concreteblocks, insulation (including pipe insulation), poles and beams,roofing, fencing, shotcrete, floating structures, concrete backfill,fire-proofing (structural, sprayed and troweled), precast structures,cast-in-place structures, pipe rack structures, and self-levelingflooring, and includes the methods of manufacturing such items orstructures using such a lightweight concrete, and the steps of providingsuch a lightweight concrete composition and the unmixed componentsthereof.

BACKGROUND OF INVENTION

Concrete is an important building material for structural purposes andnon-structural purposes alike. Concrete, generally speaking, includescementitious materials and aggregate. There may be one or more types ofcementitious material and one or more types of aggregate. Concrete mayalso include voids and reinforcing materials, such as fiber or steel rod(rebar), wire mesh or other forms of reinforcement. It can have highcompressive strength, wear-resistance, durability, and water-resistance,be lightweight, readily formed into a variety of shapes and forms, andbe very economical compared to alternative construction materials. Theformation process includes the presence of water to permit thecementitious materials to harden and to form bonds with itself, with anyaggregate, and with reinforcing materials. That hydration process, whichinvolves some of the water present being used in those chemicalreactions, is well-known and -understood.

Yet the use or value of concrete as a building material may be limitedby a number of factors. Those factors pertaining to finished structuresand products include: weight, relatively poor tensile strength,ductility, the inability to readily cut, drill or nail, and poorinsulating properties. Those factors pertaining to the concrete beforesetting include: weight, limited flowability (and/or reduced strengthcaused by adding water to overcome the same), requirement to vibrate orotherwise compact the concrete to limit voids, segregation of aggregate,and the like. Those factors pertaining to the precursor materials orcomponents supplied for use in making concrete structures or productsinclude: cost, weight, and segregation of aggregate and other materials.

Lightweight concretes have been developed to reduce the limiting effectof the weight of, among other things, finished concrete structures andproducts and uncured concrete. Such lightweight concretes (“LWC”)typically involve replacing some or all of the aggregate in a mix withanother form of aggregate that is less dense than commonly-usedaggregate. Such aggregate may be known as lightweight aggregate (“LWA”).LWCs often have lower strength (such as tensile, compressive, elasticmodulus etc.) than a comparable concrete not using LWA, but may havehigher strength-to-weight ratios due to the reduced density of theconcrete and the weight for a given structure or product.

A structural LWC is ordinarily considered to have a density betweenabout 90-120 lb/cu.ft. and a compressive strength from 2500 psi to over8000 psi. These values may be measured by ASTM C567 and ASTM C39,respectively.

A variety of characteristics of the set concrete or its behavior duringthe manufacturing process can be measured and/or designed into thatprocess. These include tensile strength, compressive strength, elasticmodulus, modulus of rupture, plastic density, bulk density, oven-drieddensity, R-value, coefficient of thermal expansion, crack resistance,impact-resistance, fire resistance, slump, water/cement ratio, pastecontent by volume, weights, and weight-fractions.

The amount or characteristics of the LWA used, or the amount of ordinaryaggregate replaced by LWA, may be constrained by the need to meetcertain minimum characteristics, including but not limited to tensilestrength, compressive strength, elastic modulus, flexural strength, ormodulus of rupture. Other constraints may include segregation of the LWAwithin the concrete.

In some cases, other materials are added to the mix or to the precursormaterials to improve one or more of the characteristics of the curedconcrete or its behavior during the manufacturing process. These may beknown as admixtures. Admixtures may be liquid or solid, but aretypically liquid unless the mix is to be kept in the dry state, such asfor making bagged concrete mix.

It is an advantage for LWC to have a reduced density, higher strengths,higher strength-to-weight ratios, and increased R-value, as well asimproved crack resistance, impact-resistance, and fire resistance.Reduction of the density and weight of the concrete offers a variety ofadvantages, including but not limited to: reduced structure weight andloading in dead loads in buildings and structures; easier and cheapertransportation and handling of the concrete products, lowertransportation costs (equipment/fuel); improved thermal insulatingproperties, fire resistance, and acoustical properties.

SUMMARY OF THE INVENTION

An embodiment of the present invention includes a self-compacting LWChaving a low density, high strength-to-weight ratio, goodsegregation-resistance, and a high R-value. Another embodiment includesa non-self-compacting LWC having a low density, high strength-to-weightratio, good segregation-resistance, and a high R-value. An embodiment ofthe present invention includes a LWC having a high replacement volume, alow weight-fraction of aggregate to total dry raw materials, andhighly-homogenous distribution of LWA.

An embodiment of the present invention includes a LWC that has a densityless than 50% of what is ordinarily found in structural LWC (about90-120 lb/cu.ft.) while having at least the minimum compressive strengthof about 2500 to 3000 psi of a structural LWC or, in another embodiment,at least a minimum compressive strength of about 3000 to 3500 psi.

An embodiment of the present invention includes a LWC that has a moremoderate replacement volume and weight-fraction of aggregate to totaldry raw materials, a highly-homogenous distribution of LWA, and adensity between about 50% and 75% of what is ordinarily found instructural LWC (about 90-120 lb/cu.ft.), while having at least a minimumcompressive strength of about 2500 psi of a structural LWC and up to orabove about 150% of that strength.

An embodiment of the present invention includes a LWC having a lowreplacement volume, a high weight-fraction of aggregate to total dry rawmaterials, a highly-homogenous distribution of LWA, and a density aboutwhat is ordinarily found in structural LWC (about 90-120 lb/cu.ft.), anda compressive strength of about two or three times the minimumcompressive strength (3500 psi) of a structural LWC.

That LWC includes a LWA that is composed of one or both of the followingtypes of particles: glass microspheres and polymer beads.

Glass microspheres, which are substantially less dense than water, areclosed-cell, smooth and non-absorptive, and vast majority of theparticles are smaller than 115 microns.

An embodiment of the invention is a LWC including a LWA composed ofglass microspheres between around 0.10 and 0.40 specific gravity (“SG”),and whose size distribution is such that about 90% are smaller thanabout 115 microns, and about 10% are smaller than about 10 microns, andthe median size is in the range of about 30-65 microns. Such glassmicrospheres may have about a 90% survival rate (i.e. they are notcrushed) at pressures ranging from about 250-4000 psi or higher.

Particular embodiments of the glass microsphere LWA include those inwhich the density is about 0.15 SG, the median size is about 55 microns,and 80% are between about 25-90 microns. Such glass microspheres haveabout a 90% survival rate at about 300 psi. Another particularembodiment of the glass microspheres is one in which the density isabout 0.35 SG, the median size is about 40 microns, and 80% are betweenabout 10-75 microns, with about a 90% survival rate at about 3000 psi.

An embodiment of the invention is a LWC including a LWA composed of amixture of two or more particular types of glass microspheres, such thatthe two or more varieties compose all of the LWA in the LWC.

An embodiment of the present invention includes a self-compacting LWCmix having a high replacement volume, a low weight-fraction of aggregateto total dry raw materials, and highly-homogenous mix properties. Anembodiment of the present invention includes a non-self-compacting LWCmix having a high replacement volume, a low weight-fraction of aggregateto total dry raw materials, and highly-homogenous mix properties. ThoseLWC mixes includes a LWA that is composed of glass microspheres and/orpolymer beads, as described above.

Embodiments of the LWC and LWC mixes include those in which otheraggregates are present in addition to one or more types of LWA. Suchordinary aggregates may include, but are not limited to, sand, andgravel. Embodiments also include LWC including LWA both with reinforcingmaterials, such as fiber or steel rod (re-bar) or wire mesh or otherforms of reinforcing, or without reinforcement.

Embodiments of the LWC and LWC mixes include cementitious materials,which may include one or more materials such as hydraulic cements,Portland cements, fly ash, silica fume (fumed silica), pozzolanacements, gypsum cements, aluminous cements, magnesia cements, silicacements, and slag cements. Cements may also be colored.

An embodiment of the present invention includes the steps of preparing aLWC mix having a high replacement volume, a low weight-fraction ofaggregate to total dry raw materials, and highly-homogenous mixproperties.

An embodiment of the present invention includes the steps of preparing aLWC mix having a more moderate replacement volume and weight-fraction ofaggregate to total dry raw materials, and highly-homogenous mixproperties.

An embodiment of the present invention includes the steps of preparing aLWC mix having a low replacement volume, high weight-fraction ofaggregate to total dry raw materials, and highly-homogenous mixproperties.

Those LWC mixes includes a LWA that is composed of glass microspheres,as described above. A mix may be prepared with liquids for formingconcrete therefrom, or as a dry mix, such as for a bagged concrete mix.A wet mix may be prepared, for example, in either a drum-type mixer, apan-type mixer, or a ribbon mixer. A dry mix may be prepared, forexample, in a pan-type mixer.

An embodiment of the present invention includes wet mix methods. Theseinclude ready mix methods, such as concrete precursor materials preparedand mixed on-site, either for use on-site or for transport, and such asconcrete precursor materials forming the unmixed components of a LWCmix, prepared for batching and mixed during transportation. Admixturesmay be added during mixing, or during batching.

An embodiment of the present invention includes dry mix methods. Theseinclude dry concrete precursor materials prepared and mixed or blendedon-site, with only dry admixtures if necessary, and bagged or otherwiseprepared for sale.

An embodiment of the present invention includes manufacturing and mixingprocesses. Such processes include a concrete manufacturer acquiringconcrete precursor materials including water (such as either by purchaseor extraction) and any admixtures, preparing batches, weighing orotherwise measuring them individually (or together in such a way as topermit the components to be measured), and providing the unmixedcomponents of a LWC mix, such as by depositing the components into aconcrete mixing truck. Such processes also include a concretemanufacturer acquiring concrete precursor materials including water(such as either by purchase or extraction) and any admixtures, preparingbatches including weighing the components individually, holding them fordelivery, and providing the components, such as by depositing thecomponents into a stationary concrete mixer or other type of mixer.

In the case of a stationary concrete mixer, such a concrete manufacturermay use the mixed concrete on-site, such as for a structure, or may be apre-caster. A pre-caster will cast concrete products on- or off-siteusing molds or forms, but those products are typically transported foruse elsewhere. Examples of pre-cast products include but are not limitedto concrete blocks, structural beams, and architectural panels.

An embodiment of the present invention includes a self-compacting LWCcomposition having a high strength after curing for 3 days, 7 days and28 days, and has a low oven-dried density, including embodiments inwhich that density is below 130, 120, 110, 100, 90, 80, 70, 60, and even40 lb./cu.ft., and embodiments at about 40 lb./cu.ft. in which thecompressive strengths are over 1200 and over about 1600 psi at 3-days,over about 1500 psi at 7-days, over about 1750 psi at 14-days, and overabout 2750, over about 3100 and over about 3800 psi at 28-days.Embodiments of the present invention at about 40 lb./cu.ft. include aself-compacting LWC composition for which the strength-to-density ratiois above about 30 and about 40 for the 3-day compressive strength, andabove about 30, about 40, and about 50 for the 7-day compressivestrength, and above about 45, about 70 and about 80 for the 28-daycompressive strength.

An embodiment of the present invention including an ordinary aggregatesuch as sand includes a self-compacting LWC composition having a highstrength after curing for 3 days, 7 days and 28 days, and has a lowoven-dried density, including embodiments in which that density is above90, and below 90, 80, 70, and even 60 lb./cu.ft., including embodimentsat or below about 60 lb./cu.ft. in which the compressive strengths areover about 1700, about 2000 and about 2200 psi at 3-days, over 1800 andabout 2750 psi at 7-days, and over about 2500 and about 4000 psi at28-days. Embodiments also include LWC with an oven-dried density over 60lb./cu.ft. in which the compressive strengths are over about 2300, andabout 3700 psi at 3-days, over about 2700 and about 4300 psi at 7-days,and over about 3000 and about 4700 psi at 10-days. Embodiments of thepresent invention at or below about 60 lb./cu.ft. include aself-compacting LWC composition for which the strength-to-density ratiois at or above about 25 and about 40 for the 3-day compressive strength,at or above about 30 and about 50 for the 7-day compressive strength,and above about 40 and about 70 for the 28-day compressive strength.Embodiments also include a self-compacting LWC composition with anoven-dried density over 60 lb./cu.ft. for which the strength-to-densityratio is at or above about 30 for the 3-day compressive strength, at orabove about 35 for the 7-day compressive strength, and above about 40for the 10-day compressive strength.

An embodiment of the present invention including an ordinary aggregatesuch as gravel includes a self-compacting LWC composition having a highstrength after curing for 7 days and 28 days, and has a low oven-drieddensity, including embodiments in which that density is about 120, about100, or below about 80 lb./cu.ft., and embodiments at about 120lb./cu.ft. in which the compressive strengths are over about 4000 andabout 5000 psi at 3-days, over about 4000, about 5000 and about 6000 psiat 7-days, and over about 4000, about 5000 and about 7000 psi at28-days.

Embodiments of the present invention at about 120 lb./cu.ft. include aself-compacting LWC composition for which the strength-to-density ratiois at or above about 35 and about 40 for the 3-day compressive strength,at or above about 40 or 50 for the 7-day compressive strength, and about50 or 55 for the 28-day compressive strength. Embodiments of the presentinvention between about 75 and 100 lb./cu.ft. include a self-compactingLWC composition for which the strength-to-density ratio is at or aboveabout 35 and about 40 for the 3-day compressive strength, at or aboveabout 40 or 45 for the 7-day compressive strength, and about 45 or 50for the 28-day compressive strength.

The above embodiments may also be LWC compositions that arenon-self-compacting.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a cutaway showing fiber-reinforced LWC.

FIG. 1B is a cutaway showing rebar-reinforced LWC.

FIG. 1C is a cutaway showing wire mesh-reinforced LWC.

FIG. 2 displays a relationship between density and thermal resistance atseveral thickness.

FIGS. 3A-3B describes the steps used to mix the concrete duringpreparation of a concrete composition.

FIG. 4 displays the process for making bagged LWC mix.

FIG. 5A displays a partially cutaway drum mixer.

FIG. 5B displays a pan mixer.

FIG. 5C displays a ribbon mixer.

FIG. 5D displays a cement truck.

FIG. 6 describes the steps at a central-mix facility for mixing aconcrete composition or for preparing and providing the components of aconcrete composition.

FIG. 7A displays an exploded view of a precast mold and product.

FIG. 7B displays an in-situ mold and product.

FIG. 8A describes the steps for mixing and manufacturing a CMU.

FIG. 8B displays a partial cutaway view of a CMU making machine andCMUs.

DETAILED DESCRIPTION

Embodiments of the invention include: (a) a LWA composed of (i) glassmicrospheres, which are less dense than water, are closed-cell, smoothand non-absorptive, and of which the vast majority of such microspheresare smaller than 105 microns; (ii) polymer beads, which are about asdense as water, are solid, smooth and non-absorptive and having a mediansize of at least about 150 microns, or (iii) a combination of suchpolymer beads and such glass microspheres, (b) a wet LWC mix comprisingsuch a LWA; (c) unmixed components of a LWC mix comprising such a LWA;(d) a dry LWC mix comprising such a LWA; (e) a LWC formed of orcomprising such a LWA; (f) manufactured or pre-cast products comprisinga LWC formed of or comprising such a LWA; (g) the process of preparingbatches of components of a LWC mix comprising such a LWA; and (h) theprocess of mixing a LWC mix comprising such a LWA.

An embodiment of the present invention includes a self-compacting LWChaving a low density, high strength-to-weight ratio, highstrength-to-density ratio, good segregation-resistance, and a highR-value. An embodiment of the present invention includes a LWC having ahigh replacement volume, a low weight-fraction of aggregate to total dryraw materials, and highly-homogenous distribution of LWA.

An embodiment of the present invention includes a LWC that has a densityabout 50%, or even less (as low as about 30 or 35 lb/cu.ft), as comparedto the ordinary value for structural LWC (about 90-120 lb/cu.ft.), andhas 28-day compressive strengths of over 1750 psi, over 2000 psi, over2500 psi and over 3000 psi. Embodiments of the present invention alsoincludes a LWC that has a density that falls at about ½ to ¾ theordinary value for structural LWC (about 90-120 lb/cu.ft.), and has28-day compressive strengths of over 2500 psi, and over 4000 psi.Embodiments of the present invention also includes a LWC that has adensity that falls in about the same range as the ordinary value forstructural LWC (about 90-120 lb/cu.ft.), and has 28-day compressivestrengths of over 5000 psi, and over 7000 psi.

A LWA of an embodiment of the invention comprises glass microspheres,which are less dense than water and preferably substantially much lessdense, are closed-cell, substantially resistant to volumetric change (ordimensional change) under pressure, smooth and non-absorptive, and vastmajority of the microspheres are smaller than 115 microns. The glassmicrospheres may range between around 0.10 and 0.60 specific gravity(“SG”), and have a size distribution such that about 90% are smallerthan about 115 microns, and about 10% are smaller than about 9 microns,and the median size is in the range of about 18-65 microns. Such glassmicrospheres may have about a 90% survival rate (i.e. they are notcrushed) at pressures ranging from about 250-28000 psi. In oneembodiment, the LWC is substantially free of either all of, or some of,such non-dimensionally and non-volumetrically stable materials such asaerogels and foamed particles and foams incorporating air bubbles suchas those formed by including air entrainment admixtures.

Through pressurization in a mercury penetrometer, microspheres and thematerials in which they are utilized can have their isostatic crushstrength measured. The crush strength distribution gets revealed byanalyzing the volume change as the pressure increases. Such data getsanalyzed by using a metric commonly referred to as the “survival rate”to which the apparent pore volume stays intact. Sphere size and wallstrength determine the crush strength. Owing to the irreversible natureof crushing, the entrapment can be up to 100%.

Particular embodiments of the glass microsphere LWA include one in whichthe density is about 0.15 SG, the median size is about 55 microns andsome 80% are between about 25-90 microns (and some 10% each are smallerthan about 25 microns and larger than about 90 microns). Such 0.15 SGglass microspheres have an approximate 90% survival rate at about 300psi. Another particular embodiment of the glass microspheres is one inwhich the density is about 0.35 SG, the median size is about 40 microns,and 80% are between about 10-75 microns (and some 10% each are smallerthan about 10 microns and larger than about 75 microns), with such 0.35SG microspheres having an approximate 90% survival rate at about 3000psi. In yet other embodiments, microspheres can be as large as 300microns.

Commercial glass microspheres are typically smooth, but the surfacecould be etched, such as by acid-washing or other methods. Without beingbound by any particular theory, it is believed that etching the surfaceof the glass microspheres may permit better adhesion between thecementitious materials and the microspheres, leading to greaterstrength, crack-resistance and other benefits. Doing so may also permitor encourage reaction between the glass microspheres and thecementitious materials.

Other types of hollow glass microspheres may have the followingapproximate characteristics. (The “80% between” column also reflectsthat some 10% each are smaller than the lower value and larger than thelarger value.):

TABLE I 90% survival Density 80% between Median size (psi): (SG) (μ) (μ)250 0.125  30-115 65 300 0.15  30-105 60 400 0.22 20-65 35 500 0.2025-95 55 750 0.25 25-90 55 2000 0.32 20-70 40 3000 0.37 20-80 45 30000.23 15-40 30 4000 0.38 15-75 40 5500 0.38 15-75 40 5500 0.38 15-70 406000 0.46 15-70 40 6000 0.30 10-30 18 7500 0.42 11-37 22 10000 0.6015-55 30 18000 0.60 11-50 30 28000 0.60  9-25 16 500 0.16 25-90 55 5000.18 15-70 35 1000 0.20 25-85 50 4500 0.32 15-60 35 10000 0.50 15-60 35

Concretes including a LWA having a higher crush strength are generallystronger. A LWA may be composed of a mixture of two or more particulartypes of glass microspheres, such that the two or more varieties composeall of the LWA in the LWC. This mixed LWA may have the advantage ofenabling the concrete design to meet certain density and/or strength orstrength-to-weight targets that would difficult with just one LWA.

Embodiments of the LWC and LWC mixes also include those in which otheraggregates are present, in addition to one or more types of LWA.Examples of such ordinary aggregates include sand, gravel, pea gravel,pumice, perlite, vermiculite, scoria, and diatomite; concrete aggregate,expanded shale, expanded slate, expanded clay, expanded slag, pelletizedaggregate, tuff, and macrolite; and masonry aggregate, expanded shale,clay, slate, expanded blast furnace slag, sintered fly ash, coalcinders, pumice, scoria, pelletized aggregate and combinations of theforegoing. Other ordinary aggregates that may be used include but arenot limited to basalt, sand, gravel, river sand, river gravel, volcanicsand, volcanic gravel, synthetic sand, and synthetic gravel.

In one embodiment, the LWC is free or substantially free of porous glassspheres (i.e., glass spheres having a porous surface). In anotherembodiment, the LWC is free or substantially free of porous glassspheres that lack a hollow vacuum center.

In any of such cases, the total aggregate volume fraction and weightfraction can be accounted for in this manner:

100%=f _(LWA1) +f _(LWA2) + . . . f _(LWAn) +f _(Agg1) +f _(Agg2) + . .. f _(Aggm)   [01]

Here the number of types of LWA is from 1-n, and the number of types ofordinary aggregates is 1-m, and the f_(LWA)+f_(Agg) values reflecteither the weight fraction of that component or its volume fraction, asappropriate.

Moreover, the volume and weight of the total aggregate can be describedin the following manner:

Agg_(T)=LWA₁+LWA₂+ . . . LWA_(n)+Agg₁+Agg₁+ . . . LWA_(m)   [02]

Here the LWA and AGG values reflect either weight of that component orits volume, as appropriate. In an embodiment of the invention in whichthere is just one type of LWA and one ordinary aggregate, such as sand,these calculations may be simplified thusly:

f _(LWA) +f _(Sand)=100%   [03]

LWA+Sand=Agg_(T)   [04]

In an embodiment of the invention in which there is just one type of LWAand two ordinary aggregates, such as sand and gravel, these calculationsmay be simplified thusly:

f _(LWA) +f _(Sand) +f _(Grav)=100%   [05]

LWA+Sand+Gravel=Agg_(T)   [06]

Embodiments of the LWC and LWC mixes include cementitious materials. Inembodiments of the invention, the LWC and LWC mixes include a hydrauliccement, Portland cement, including a Type I, Type I-P, Type II, TypeI/II (meeting both Types I and II criteria) or Type III Portland cement,fly ash, and silica fume. These cementitious materials undergo achemical reaction resulting in the formation of bonds with itself andother cementitious materials present, with any aggregate, and withreinforcing materials.

Such exemplary cement types are as defined in ASTM C150, and may begenerally described as having the following particularly appropriateuses: Type I (general), Type I-P (blended with a pozzolan, including flyash), Type IA (air-entraining Type I), Type II (general—with need formoderate sulfate resistance or moderate heat of hydration), Type IIA(air-entraining Type II), Type III (with need for high early strength),and Type IIIA (air-entraining Type III). As is known to those of skillin the art, Portland cements are powder compositions produced bygrinding Portland cement clinker, a limited amount of calcium sulfatewhich controls the set time, and up to 5% minor constituents (as allowedby various standards). As is known to those of skill in the art,Portland cements are powder compositions produced by grinding Portlandcement clinker, a limited amount of calcium sulfate which controls theset time, and minor constituents (as allowed by various standards). Thespecific gravity of Portland cement is typically about 3.15. In anembodiment of the invention, the cement includes a HOLCIM brand TypeI/II Portland cement component, in particular HOLCIM St. Genevieve TypeI/II.

Fly ash is a cementitious material that is a byproduct of coalcombustion. Pulverized coal is burned in the presence of flametemperatures of to 1500 degrees Celsius. The gaseous inorganic mattercools to a liquid and then solid state, forming individual particles offly ash.

Types of fly ash include Class C and Class F. Based upon ASTM C618,Class F fly ash contains at least 70% pozzolanic compounds (silicaoxide, alumina oxide, and iron oxide), and Class C fly ash containsbetween 50% and 70% of these compounds. Such fly ash can reduce concretepermeability, with Class F tending to have a proportionately greatereffect. Class F fly ash also protects against sulfate attack, alkalisilica reaction, corrosion of reinforcement, and chemical attack. Thespecific gravity of fly ash may range from 2.2 to 2.8.

Fly ash, as a cementitious material reacts with water present in themix. Fly ash is believed to improve workability of the cement mixtureonce mixed with water. In addition, use of fly ash holds downmanufacturing costs, as it is less expensive by weight than eithercement or microspheres. In one embodiment of the invention, BORAL brandClass F Fly Ash is used, with an SG of 2.49. In another embodiment ofthe invention, MRT Labadie brand Class C Fly Ash is used, with an SG of2.75.

Silica fume is a cementitious material that is a powdered form ofmicrosilica. Silica fume, as a cementitious material reacts with thecalcium hydroxide in the cement paste present in the mix. It is believedto improve strength and durability of the concrete product, byincreasing the bonding strength of the cementitious materials in theconcrete mix and reducing permeability by filling voids in among cementparticles and the LWA (such as the glass microspheres). Silica fume canhave an SG of around 2.2. In one embodiment of the invention, EUCONbrand MSA is used, with an SG of 2.29.

It is believed that the LWA, for example the glass microspheres, used inthe present invention may also be reacting with the above cementitiousmaterials in the hydration process. In this case, the amount ofcementitious materials considered to be present in a mix should accountfor that capability. A way to account for it is by evaluating theeffective mass of cementitious materials (CM_(EFF)) where that value isexperimentally derived to capture the effect of the LWA present in themix on the workability of the mix and strength of the concrete. If M_(C)is the mass of the cement, M_(SF) is the mass of the silica fume, andM_(FA) is the mass of the fly ash, and MLWA represents the mass(es) ofthe one or more LWAs present, and λ is a scaling factor for theeffective cementitious mass of that LWA, then a way to express theresult is (if for example there are two LWAs present):

CM_(EFF) =M _(C) +M _(SF) +M _(FA)+λ₁ ·M _(LWA1)+λ₂ ·M _(LWA2)   [07]

In an embodiment of the invention, the amount of water in the wet mixwill depend in many instances on the desired water-to-cement (W/CM)ratio and amount of cement or cementitious materials in the concretemix. In general, a lower W/CM ratio results in stronger concrete butalso in a lower slump value and reduced workability and ability for thewet concrete mix to flow. More water is usually used in mixing concretethan is required merely for workability. But thinning the paste reducesits strength. Admixtures can be used to reduce the amount of waterneeded for workability, but at the cost of increased manufacturing costsdue to the expense of the admixtures. Ordinarily, a minimum W/CM ratiois 0.22 to permit sufficient hydration for the concrete to set properly.W/CM ratios can range upward therefrom to about 0.40, from about0.57-0.62, about 0.68 or above, and at levels ranging between any of thevalues stated above. W/CM ratios around 0.22, or in the range of about0.15-0.35, ordinarily are present in the case of the manufacture ofconcrete blocks, with the values for other concrete being higher. Ahigher W/CM ratio can be tolerated in multiple instances, including whenthe concrete's design strength and strength-to-weight ratios are higher.A higher ratio is also tolerable in the event the glass microspheres arereacting with cementious materials, allowing for a portion of such glassmicrospheres to be used in the cementious material calculations, therebylowering the W/CM ratio.

The W/CM ratio accounts for all water (here potable water), excludingwater in any admixtures. This ratio is calculated by dividing the weightof that water by the total weight of all cementitious materials. Thatratio can also be calculated by dividing the weight of that water byCM_(EFF), the effective weight of the cementitious materials.

As shown in FIGS. 1A-1C, embodiments of the invention could also includeLWC 1 including reinforcing materials, such as fiber 2 or steel rod(re-bar) 3 or wire mesh 4, and LWC mixes including reinforcingmaterials, such as fiber, as well as the processes of preparing and/orbatching them. A fundamental function of reinforcing materials is toincrease tensile strength and resist tensile stresses in portions of theconcrete where cracking as well as other structural failures mightotherwise occur. In particular, inclusion of fiber in a concrete mix canhelp reduce plastic shrinkage and thermal cracking and to improveabrasion resistance, as well as flexural characteristics of concreteproducts. Fiber is believed to bond with the concrete.

Suitable fibers may include glass fibers, silicon carbide, PVA fibersaramid fibers, polyester, carbon fibers, composite fibers, fiberglass,steel fibers and combinations thereof. The fibers or combinationsthereof can be used in a mesh or web structure, intertwined, interwoven,and oriented in any desirable direction, or non-oriented andrandomly-distributed in the LWC as shown in FIG. 1A, or LWC mix. In anembodiment of the invention, a short, small diameter, monofilament PVA(polyvinyl alcohol) fiber is used, which meets ASTM C-1116, Section4.1.3 (at 1.0 lb/cu.yd). A particular example of such fiber is a NYCONbrand PVA RECS15, having an 8-denier (38 micron) diameter, 0.375″ (8 mm)length, about 1.3 (or 1.01) SG and a tensile strength of 240 kpsi (1600Mpa) and a flexural strength of 5,700 kpsi (40,000 Mpa). The fiberamount may be adjusted to provide desired properties to the concrete.

An embodiment of the LWC mix may include admixtures to improve thecharacteristics of the mix and/or the set concrete. Such admixtures caninclude an air entrainment admixture, a de-air entrainer admixture, asuperplasticizer (or high range water reducer), a viscosity modifer (orrheology-modifier), a shrinkage reducer, an expansive agent, latex,superabsorbent polymers, a hydration stabilizer (or set retardingadmixture) or any combination of any of the foregoing. The admixturesmay also include colorants, anti-foam agents, dispersing agents,water-proofing agents, set-accelerators, a water-reducer (or setretardant), bonding agents, freezing point decreasing agents,anti-washout admixtures, adhesiveness-improving agents, air or anycombination of any of the foregoing. The admixture(s) may be determinedon a weight basis (e.g. in ounces or lbs.), based on the amount per 100lbs of cementitious materials. Such admixtures typically form less thanone percent by weight with respect to total weight of the mix (includingwater), but can be present at from amounts below 0.1 to around 2 or 3weight percent, or at amounts therebetween or at higher amounts, such asaround 3 to 5 weight percent or around 4 to 6 weight percent or higheror by ounces per 100 lbs. of cement material. By ounces per 100 lbs. ofcement material, admixtures may be present in ranges from zero to aboutfifty (and much higher for certain types, such as latex) includingranges from 0-5, 5-10, 5-15, 15-20, 15-25, 20-30, 25-35, 30-40 and 40-50fl. oz./100 lbs. of cementitious materials. By lbs. per 100 lbs. ofcementitious materials, admixtures may be present in ranges from zero toabout fifty (and much higher for certain types, such as latex) includingranges from 0-5, 5-10, 5-15, 15-20, 15-25, 20-30, 25-35, 30-40 and 40-50fl. oz./100 lbs. of cementitious materials.

Exemplary plasticizing agents include, but are not limited to,polyhydroxycarboxylic acids or salts thereof, polycarboxylates or saltsthereof; lignosulfonates, polyethylene glycols, and combinationsthereof.

A superplasticizer permits concrete production with better workabilitybut with a reduced amount of water, assists in forming flowable andself-compacting concrete. Exemplary superplasticizing agents includealkaline or earth alkaline metal salts of lignin sulfonates;lignosulfonates, alkaline or earth alkaline metal salts of highlycondensed naphthalene sulfonic acid/formaldehyde condensates;polynaphthalene sulfonates, alkaline or earth alkaline metal salts ofone or more polycarboxylates; alkaline or earth alkaline metal salts ofmelamine/formaldehyde/sulfite condensates; sulfonic acid esters;carbohydrate esters; and combinations thereof. In one embodiment, EUCONbrand SPC is used, which is a polycarboxylate-based superplasticizer. Inother embodiment, BASF brand Glenium 7500 is used.

An air entrainment admixture assists in forming small or microscopic airvoids in the set concrete that results from a favorable size and spacingof air bubbles in the concrete mix. This helps protect the concrete fromfreeze/thaw cycle damage. It also improves W/CM ratio, resistance tosegregation of components, workability, resistance to de-icing salts,sulfates, and corrosive water. An exemplary air entrainment admixturemeets ASTM C260. In one embodiment, Euclid Chemical AEA-92 is used. Inanother embodiment, the LWC is free or substantially free of an airentrainer.

A de-air entrainer admixture (or air detrainer admixture) acts to reducethe entrained air (or plastic air content). This helps to mitigate thereduced strength caused by entrained air (i.e. the volume comprising airlacks the strength of cement or aggregate) and also reduces the need tooverdesign the concrete or object due to that decrease in strength. Airmay be present in the mix from a number of sources, including: airentrained as a result of other admixtures (such as polycarboxylate basedhigh-range water reducers); air entrained with aggregate; and airmechanically mixed into the mix. Admixtures may also increase the effectcaused by the other two sources. Without being bound by any particulartheory, it is believed that LWA having a high relative surface area (asa result of small size) may also increase this effect, and result in anexcessively high air content. Adding an air detrainer can thus reducethe air to a desirable level. Exemplary air detrainers include but arenot limited to those based upon tributyl phosphate in a range of about3.0 to about 7.0 weight percent, and acetic acid in a range of about 1.0to about 5.0 weight percent, and is sold commercially as BASF brand PS1390 (or MasterSure 1390). PS 1390 may be applied at about 0.2-3.0 oz.or about 0.2-1.0 oz., both per 100 lbs. of the cementitious materials.Other examples of air detrainers suitable for achieving reduction in airpores are products based on polyalkylene oxides, such as adducts ofethylene oxide or propylene oxide with alcohols or phenols; phosphatessuch as tributyl phosphate or triisobutyl phosphate, phthalates such asdibutyl phthalate, siloxanes such as polydimethylsiloxane, or phosphatesof ethoxylated fatty alcohols, such as ethylene oxide stearyl phosphate.Suitable air detrainers are described in U.S. Patent Publication No.2002/0132946 and U.S. Pat. No. 6,545,067, both of which are incorporatedby reference.

A viscosity modifier (or rheology-modifying admixture), promotesformation of self-consolidating concrete by modifying the rheology ofconcrete, specifically by increasing the viscosity of the concrete whilestill allowing the concrete to flow without segregation of aggregate orother materials in the mix. The increased viscosity permits smallparticles, including LWA such as the glass microspheres, to remainsuspended in the mix, rather than segregating by sinking or floating orrising to the top. An exemplary admixture meets ASTM C494 Type S.Exemplary viscosity modifiers include but are not limited to those basedupon or including 5-chloro-2-methyl-2H-isothiazol-3-one, and is soldcommercially as GRACE brand V-MAR 3. V-MAR 3 may be applied at about4-16 oz. per 100 lbs. of the cementitious materials. Other exemplaryviscosity modifiers include but are not limited to those based upon orcontaining quinolone, sodium hydroxide/[1,1′-Biphenyl]-2-ol, sodium salt(1:1) (or sodium sulfate) and is sold commercially as EUCON brand AWA.AWA may be applied at about 10-32 oz. per 100 lbs. of the cementitiousmaterials. Other exemplary viscosity modifiers include but are notlimited to those based upon or containing [1,1′-Biphenyl]-2-ol in arange of about 0 to about 0.2 weight percent or about 0.1 to about 1.0weight percent, and ethylene glycol in a range of about 0 to about 1.0weight percent or about 0.5 to about 1.5 weight percent, and sulfuricacid, and is sold commercially as BASF brand MasterMatrix VMA 362. VMA362 may be applied at about 2-14 oz. per 100 lbs. of the cementitiousmaterials.

A shrinkage reducer (or surface-tension reducing admixture or shrinkagereducing admixture) reduces shrinkage during the curing process causedby drying, which can create tensile stresses and induce cracking. Theshrinkage reducer may operate by decreasing the surface tension of thewater in the composition, thereby reducing the capillary tension createdby water menisci in pores within the composition. Suitable shrinkagereducers include but are not limited to those based upon neopentylglycol, alklyene glycol (such as 1,6-hexanediol, 1,5-pentanediol,1,4-pentanediol, and 2-methyl-2,4-pentanediol), or a secondary and/ortertiary dihydroxy C3-C8 alkane, such as 2-methyl-2,4-pentadiol(hexylene glycol). Another exemplary shrinkage reducer is based upon amixture of propylene oxide, 1,4-dioxane, and ethylene oxide and is soldcommercially as BASF brand MasterLife SRA 20. Another exemplaryshrinkage reducer is based upon propylene glycol, and may be applied atabout 1.0-1.5 lbs. per 100 lbs. of the cementitious materials or about1.15 lbs. per 100 lbs. of the cementitious materials. Other shrinkagereducers can reduce shrinkage during the curing process by causing theconcrete to expand during that process. This induces a compressivestress to offset tensile stresses caused by drying shrinkage. Suchshrinkage reducers may also include an expansive agent. One exemplaryadmixture includes, by weight, 30-60% poly ethylene glycol mono butylether, 15-40% 2-(2-(2-Butoxyethoxy)ethoxy)ethanol, 15-40% tetra ethyleneglycol mono butyl ether, 15-40% glycol ether solvent, and 0.1-1% sodiumhydroxide, and has an SG of about 1.002, and is sold commercially asEUCON brand SRA-XT. SRA-XT may be applied at about 1 lb. per 100 lbs. ofthe cementitious materials in air entrained applications, and up to 2lbs. per 100 lbs. of the cementitious materials in non-air entrainedapplications.

An expansive agent could be also be used separately from the shrinkagereducer, or with it. Differing materials may serve as expansive agents,but they have in common the ability to cause an expansion of theconcrete during curing. This may be accomplished by carrying outparticular chemical reactions during the curing process. Non-limitingexamples of expansive agents include calcium oxide (CaO) and calciumsulfo-aluminate ((CaO)₄(Al₂O₃)₃(SO₃). Use of CaO expansive agentproduces a calcium hydroxide platelet crystal system based on calciumaluminate/calcium hydroxide; in particular, lime (CaO) is transformedinto calcium hydroxide (Ca(OH)₂). Calcium sulfo-aluminate, with lime andanhydrite (CaSO₄), are converted into ettringite. Calcium oxide andcalcium sulfo-aluminate are appropriate for use with reinforcedconcrete. One exemplary admixture includes, by weight, over 60% calciumoxide (CaO), 15-40% fly ash, 3-7% Portland cement, 3-7% sodiumlignosulfate and under 1% crystalline silica/silica sand, and has an SGof about 3.15, and is sold commercially as Euclid Chemical brand Conex.Conex may be applied at about 3-6 weight percent of the cementitiousmaterials to reduce shrinkage and at about 6-10 weight percent of thecementitious materials to compensate for shrinkage. Calcium oxide mayalso be applied at about 10 lbs. per 100 lbs. of cementitious materials.

An admixture may combine a shrinkage reducer and an expansive agent. Inone embodiment Conex and SRA-XT are used together. Another suchadmixture includes MgO that has been lightly burnt (between 750-1200°C.) with a shrinkage reducing agent and a super absorbent polymer, wherethe shrinkage reducing agent is present by weight as about 7-25%,13-25%, or 17.5-25% of the MgO and the super absorbent polymer ispresent as about 0-7% of the MgO (or at 0.1-12% or 2-7% with W/CM ratiosless than or equal to 0.38), and is sold commercially as a free-flowablepowder as Premier Magnesia brand PREVent-C. PREVent-C may be applied maybe applied at about 5 weight percent of the cementitious materials.

Latex increases bonding within the concrete, reduces shrinkages andincreases workability and compressive strength. Latex is a polymer, andEuclid Chemical FLEXCON and BASF brand STYROFAN are examples.

Superabsorbent polymers can improve curing of the concrete, including byproviding internal water curing, that is by serving as an internalreservoir of water that is not part of the mix water (thus keepingwater/cement ratio down). That internal water is usable for the curingprocess to promote curing (and, thus strength) and mitigate againstshrinkage (which may induce cracking). Reducing the mix water can alsoreduce slump during the curing process. Superabsorbent polymers are aform of polymer that can absorb large volumes of water relative to theirdry volume, swell, and then reversibly release that water and shrink.Polyacrylic acids are an example. They may be used with lowerwater/cement ratios (such as below 0.45 or below 0.42 or lower).

A hydration stabilizer (or set retarding admixture) permits concreteproduction with better predictability by retarding the setting of theconcrete to permit time for activities such as mixing, transport,placing and finishing. By reducing the need to add water (therebydecreasing the W/CM ratio) to delay setting during these activities, awater-reducer can improve strength and reduced permeability. Anexemplary admixture meets ASTM C494 Type D, and in one embodiment isEUCON brand STASIS, and in another embodiment is BASF brand Delvo.

A water-reducer (or set retardant) permits concrete production withbetter predictability by retarding the setting of the concrete to permittime for activities such as mixing, transport, placing and finishing. Byreducing the need to add water (thus increasing the W/CM ratio) to delaysetting during these activities, a water-reducer can improve strengthand reduce permeability. Exemplary water reducers includelignosulfonates, sodium naphthalene sulfonate formaldehyde condensates,sulfonated melamine-formaldehyde resins, sulfonated vinylcopolymers,urea resins, and salts of hydroxy- or polyhydroxy-carboxylic acids, a90/10 w/w mixture of polymers of the sodium salt of naphthalene sulfonicacid partially condensed with formaldehyde and sodium gluconate andcombinations thereof. An example of a water-reducer is EUCON brand NR.

The concrete composition can include the above components at above anyof the lower levels of weight percent indicated in Table II, below anyof the higher levels indicated, or at levels within the rangesindicated.

TABLE II Material More preferable wt. % Preferable wt. % Cement 32-4430-46 32-36 30-38 35-41 33-43 41-43 40-55 Fly Ash  0-12  0-14  8-12 7-14 Silica Fume 0.4-2.0 0.3-4.5 1.4-4.1 1.0-4.5 1.4-2.0 1.0-2.5Microspheres (SG 0.15) 0.0  0-11  5-10  3-11 5.0-5.5 4.5-6.0  8.5-10.0 8.0-10.5 Microspheres (SG 0.35) 0.0  0-15   13-20.5 11.5-21.5 19.0-20.518.0-21.5 13.0-14.0 12.0-15.0 Microspheres 0.0  0-11  5-10  0-15 5.0-5.5 3-11  8.5-10.0 4.5-6.0   13-20.5  8.0-10.5 13.0-14.0 11.5-21.519.0-20.5 12.0-15.0 22-24 18.0-21.5 26-28 20-25 20-30 Polymer beads (SG~1.06) 20-30  0-50 45-55 10-75 60-75 Polymer beads 16-35  0-60 35-65 6-80 50-80 Fiber .30-.50 0.0-1.0 Water 16-20 12-22 24-35 21-38 24-2522-27 31-35 29-37 Air Entrainer .004-.010 .0035-.0105 (as fl. oz./cwt)0.15-0.30 1-5 0   0-1 De-air entrainer  .15-0.35 0.0-0.4 (as fl.oz./cwt)  5-15  0-15  5-11 HRWRA 1.0-2.1  .5-2.5 (as fl. oz./cwt) .054-1.001 .0500-1.050 15-45 10-65 15-38 Viscosity Modifier  0.2-0.350.0-0.5 (as fl. oz./cwt) .150-.034  0.0-.037 .21-.30 .19-.32 .24-.30.22-32  5.5-10.5  2-18  5-14 Hydration Stabilizer 0.06-0.07 0.0-.1  (asfl. oz./cwt) .055-.075 .05-.08  .055-.0565 .045-.065 .060-.075 .050-.0851.8-2.2 1-8 WRA/Retarder .13-.15 .1-.2 (as fl. oz./cwt) 4.5-5.5 0-5Shrinkage Reducing 1.0-1.2 0.0-1.5 (as fl. oz./cwt) 10-55  0-60 30-60Latex 15-17  0.0-20.0 (as fl. oz./cwt) 200-400  0-600 Expansive Agent(lbs./cwt)  2-15  0-15 3-6  6-10 Comb. Shrinkage Reducing  1-15 0-6 &Expansive Agent (lbs./cwt) 4.5-5.5 4-6 (as fl. oz./cwt)  0-30  0-30

Higher-density/higher-strength forms of the concrete composition canalso include the above components at above any of the lower levels ofweight percent indicated in Table IIA, below any of the higher levelsindicated, or at levels within the ranges indicated.

TABLE IIA Material More preferable wt. % Preferable wt. % Cement 25-3515-40 30-34 18-34 18-28 16-30 Fly Ash 4.5-9.0  4-10 4.5-7.5 4-8Microspheres (SG 0.15) 0.0  0-11 5.0-5.5 3-8 Microspheres (SG 0.35)  0-2.5  0-15 13-15  7-16 2.5-3.5 2-9  6-11  5-11 Microspheres 0.0  0-115.0-5.5  0-15   0-2.5 3-8 2.5-3.5  7-16 13-15 2-9  6-11  5-11 16-1815-20 18-22 15-25 Gravel (coarse aggr.) 0.0  0-60 38-53 35-55 44-4642-48 Sand (fine aggr.) 0.0  0-70 15-40 14-70 16-20  0-22 17-19 16-22Polymer beads (SG ~1.06)  5-20  0-50 15-25  5-50 20-30 40-50 Polymerbeads  2-25  0-50 10-40  2-60 15-35 Fiber .20-.40 0.0-1.0 .19-.31.15-.35 Water  9-27  8-30 23.5-25.5 22-27  7-16  5-20 7.5-8.5  6.5-10.0Air Entrainer 0.004-0006  0.0-0.1 (as fl. oz./cwt) 0.15-0.30 1-5 0 0-1De-Air Entrainer .15-.25 0.0-0.3 (as fl. oz./cwt)  9-11  5-15 HRWRA .5-1.0  .4-1.1 (as fl. oz./cwt) .45-.52 .40-.75 28-32 15-45 ViscosityModifier .14-.26 .10-.35 (as fl. oz./cwt) .11-.16 .08-.26 7-9  2-18Hydration Stabilizer .03-.06 .02-.07 (as fl. oz./cwt) .030-.035 .01-.051.8-2.2 1-8 Shrinkage Reducing 0.4-0.8 0-1 (as fl. oz./cwt) 0.4-1.10.0-1.5 10-55  0-55 30-34 46-50 Latex 15-17  0.0-20.0 (as fl. oz./cwt)200-400  0-600 Expansive Agent (lbs./cwt)  2-15  0-15 3-6  6-10 Comb.Shrinkage Reducing  1-15 0-6 & Expansive Agent (lbs./cwt) 4.5-5.5 4-6(as fl. oz./cwt)  0-30  0-30

In addition to the mass and volume of the individual components and theW/CM ratio, other characteristics of interest of the concrete mixinclude total cementitious content (in lb./cu.yd), paste content byvolume (incl. air) and replacement volume of the LWA.

Total cementitious content is a measure of density of the cementitiousmaterials in the wet mix concrete, and may be measured in pounds percubic yard. In embodiments of the invention, the total cementitiouscontent ranges from around 660 to around 700 lbs., around 750 lbs. andaround 800 lbs, and around 825 lbs or below. Higher values tend tocorrelate with higher-strength concretes. In other embodiments, such asthose including sand and/or coarse aggregate, the total cementitiouscontent is about 800 lbs. and ranging from around 750 lbs. to around 825lbs.

The paste content by volume is a percentage measure of the non-aggregatecontent of the wet mix (including cementitious materials, water, and theplastic air content of that mix). The paste content by volume togetherwith the total volume displaced the aggregates is equal to 100%. Inembodiments of the invention, the paste content by volume is about 50%,ranging from 49.1% to 50.6%, or higher with an increase in density. Inother embodiments, such as those including sand and/or coarse aggregate,the paste content by volume is about 40% or about 50% ranging from 35%to 55%, or lower with an increase in density.

The replacement volume of the LWA (V_(R)) is the volume percentagedisplaced by the LWA in the wet mix, whether it is a single type of LWAor a mix of more than one type. In a mix having no ordinary aggregate(for instance, sand), the replacement volume is the volume percentagedisplaced by the LWA. In embodiments of the invention, V_(R) may beabout 50%, ranging from 49.6% to 53.4%, for mixes with no ordinaryaggregate, around 10%, 30% or 40% (as density drops), and ranging fromabout 10% to about 43%, for mixes including sand, and around 17% or30-35% (as density drops), and ranging from about 16% to about 37%, formixes including coarse aggregates (and possibly sand). V_(R) may also beat other levels ranging between any of levels stated above.

Fresh concrete has certain characteristics of interest, including slump,plastic air content, workability and plastic density.

Slump is an important measure of the workability of a concrete mix.Slump is a measure of how easily a wet mix flows. Slump is measured ininches, and may be measured according to ASTM C143. Neither particularlyhigh nor particularly low values are inherently preferable. Extremelylow-slump applications include the manufacture of concrete blocks andother products. Low-slump applications include circumstances in whichearly form removal is necessary or desired, or when the concrete mustotherwise be immediately self-supporting (or nearly so—“0” slump) suchas troweled-on applications. Normal-slump applications includescircumstances in which pumpability is critical, such as when concretemust be pumped. In embodiments of the invention, slump ranged from about5 to almost 40, including values around 5, 6, 8, 22, 25, 28, 32, and 38.

Plastic air content is a measure of the percentage of the volume of thewet mix that constitutes air entrained in the mix, and may be measuredaccording to ASTM C231. A desirable target plastic air content may rangefrom about 5.0% to 6.5%. In embodiments of the invention, the valueranged from 4.0% to 13.0%. In other embodiments of the invention, thevalue ranged from 2.4% to 2.8%, 4.0% to 6.0%, and 4.0% to 8.0% and evenmight be as low 2%, 1% or about 0%.

Plastic density is a measure of the density of the wet mix, and may bemeasured according to ASTM C138. In embodiments of the invention, thevalue ranged from around 50 lb./cu.ft. to around 55 lb./cu.ft.,including about 52 lb./cu.ft., for lighter weight compositions, andaround 70 lb./cu.ft., including about 69 lb./cu.ft., 74 lb./cu.ft., 88lb./cu.ft. and 125 lb./cu.ft, for heavier weight compositions. Forembodiments of the invention including coarse aggregrate, such asgravel, the value ranged from around 85 lb./cu.ft. to around 130lb./cu.ft., including about 85 lb./cu.ft., about 100 lb./cu.ft. andabout 125 lb./cu.ft. The composition elements were present in an amounteffective to achieve a target density in said cured composite of notmore than those densities.

Cured concrete has many characteristics of interest, including bulkdensity, oven-dried density, thermal conductivity and insulation value(or R-value), permeable porosity, modulus of rupture, compressivestrength, elastic modulus, tensile strength, resistance to fire andcombustibility, freeze/thaw resistance, drying shrinkage, chloride ionpenetrability, abrasion resistance, the ring test, and CTE (coefficientof thermal expansion).

Compressive strength is a measure of the ability of the concrete toresist compressive loads tending to reduce its size until its failure,and may be measured according to ASTM C39. Higher compressive strengthand strength-to-weight are an advantage with the invention because lessweight reduces costs. This is the case, for example, in applicationssuch as transportation and dead loads. Concrete compressive strengthincreases as the concrete ages, at least up to a point, and thehydration process (the chemical reaction within the cementitiousmaterials) continues. Tests may be carried out at, for instance, 3, 4,7, 14, and 28 days or even longer, as well as at other intervals. Inembodiments of the invention, the measured values ranged as follows:3-day: about 1100, about 1300, about 1700, about 2200 psi, about 2300psi, about 3800 psi, about 2900 psi, about 4400 psi, and about 5000 psi;4-day: about 1900 psi; 7-day: about 1300, about 1400, about 1600, about1900, about 2600 and about 2750 psi, about 4400 psi, about 3200 psi,about 5100 psi, about 6000 psi, about 4700 psi; 10-day: about 3100 psi,about 4800 psi; 14-day: about 3000 psi; 28-day: about 2500 psi, about2800, about 3300, about 4000, about 3400 psi, about 1770 psi, about 1750psi, about 3800 psi, about 7000 psi, about 5100 psi and higher.

Elastic modulus is a measure of the concrete's tendency to be deformedelastically when a force is applied to it, and may be measured accordingto ASTM 649. Like compressive strength, elastic modulus increases as theconcrete ages. Tests may be carried out at, for instance, 3, 7 and 28days or even longer or at other intervals. In embodiments of theinvention, the measured values ranged as follows: 3-day: about 400,about 500, about 650, about 850, about 1350, 2100 and about 3400 kpsi;7-day: about 500, about 550, about 600, about 650, about 800, about 900,about 1400, about 2300 and about 3500 kpsi; 10-day: about 1400 and 2900kpsi; 14-day: about 800 kpsi; 28-day: about 800, about 850, about 900,about 600, about 700, about 1100, about 550, about 1600, about 2400 andabout 4200 kpsi and higher.

Tensile strength, or ultimate tensile strength, is a measure of themaximum stress that the concrete can withstand while being stretched orpulled before failing or breaking, and may be measured by ASTM C496.Like compressive strength, tensile strength increases as the concreteages. Tests may be carried out at, for instance, 3, 7 and 28 days oreven longer or at other intervals. In embodiments of the invention, themeasured values ranged as follows: 3-day: about 130, about 140, about160, about 200, about 230, about 300, about 320, about 420 and about 530psi; 7-day: about 180, about 200, about 230, about 240, about 300, about330, about 460, about 365 and about 640 psi; 14-day: about 360 psi;28-day: about 260, about 235, about 260, about 300, about 340, about420, about 390, about 480, and about 620 psi and higher.

Modulus of rupture (or flexural strength) is a measure of the concrete'sability to resist deformation under load, and may be measured accordingto ASTM C78. In embodiments of the invention, the measured values at 28days ranged as follows: about 300, about 330, about 350, about 270,about 410, about 450, about 610, and about 910 psi and higher.

Oven-dried density is a measure of the density of a structurallightweight concrete, and may be measured according to ASTM C567. Inembodiments of the invention, the measured values ranged as follows:about 36, and from about 39 to 42 lb/cu.ft., and about 55-60 lb/cu.ft.,as well as about 75-80 lb/cu.ft., about 100 lb/cu.ft., and about 120lb/cu.ft. Oven-dried densities of from about 35 to about 120 lb./cu.ft,below 35, between about 35 and about 40, below 40, below 45 lb/cu.ft.,about 60, about 70, about about 80 lb/cu.ft., about 90, about 100, andabout 120 lb/cu.ft.may all be useful.

R-value is a measure of the insulating effect of a material. Wherethickness (T) is in inches, and thermal conductivity CT is in(Btu-in.)/(hr-°F.-sq.ft), R-value is defined as T/C_(T). C_(T) andR-value each have a non-linear relationship with the oven-dried densityof concrete; the relationship is an inverse one for R-value. Thisrelationship is depicted in FIG. 2, which displays the approximatethermal resistance (in R-value) for oven-dried concretes at 4″, 5″ and6″ thickness. R-value may be influence by actual moisture content andthe thermal conductivity of the material used in the concrete. Forconcrete blocks (concrete masonry units) the R-values are about: 4″block: 0.80; 8″ block: 1.11; 12″ block: 1.28. For ordinary concrete theR-values are (at the listed density, in lb/cu.ft.) at 1″ thickness: 60:0.52; 70: 0.42; 80: 0.33; 90: 0.26; 100: 0.21; 120: 0.13. R-value forembodiments of the invention, based upon measured and expected oven-drydensity, are expected to be (at the listed density, in lb/cu.ft.) at 1″thickness: 40: 1.06; 60: 0.75; 70: 0.56; 90: 0.43; 100: 0.37; 110: 0.25and higher.

Bulk density may be measured according to ASTM 642. The permeable porespercentage may be measured according to ASTM 642. The resistance to firemay be measured according to ASTM E136. The combustibility may bemeasured according to ASTM E119.

Freeze/thaw resistance may be measured according to ASTM C666, and is ameasure of the concrete's resistance to cracking as a result of enduringfreeze/thaw cycling.

Drying shrinkage may be measured according to ASTM C157, and is ameasure of the percentage of volumetric reduction in size caused by thedrop of the amount of water in the concrete as it dries. It can bemeasured as ‘moist’ at 7 days, and as ‘dry’ at 28 days.

Chloride ion penetrability may be measured according to ASTM C1202, andis a measure of the ability of the concrete to resist ions of chlorideto penetrate. In embodiments of the invention, the measured valuesranged as follows (in coulumbs): about 133 to 283.

Abrasion resistance may be measured according to ASTM C779, and is ameasure of the ability of the concrete's surface to resist damage fromabrasion. In embodiments of the invention, the measured values ranged asfollows (in inches): about 0.032 to 0.036 and may be lower or higher.

The ring test may be measured according to ASTM C1581, and is a measureof the ability of the concrete to resist nonstructural cracking. Inembodiments of the invention, the measured values ranged as follows (indays): about 10.1 to 16.2 and may be and higher.

CTE is the coefficient of thermal expansion and may be measuredaccording to AASHTO T 336. In one embodiment of the invention, themeasured value was (in in./in./°F.): 5.70×10⁻⁶.

To further illustrate various illustrative embodiments of the presentinvention, the following examples of concretes made and test results andmeasurements therefrom are provided.

EXAMPLES Examples 1-7 Aggregate: SG 0.35 Microspheres

Concrete preparation and mixing was done in accordance with ASTM C192.The process is described in reference to FIGS. 3A-3B. First, allnecessary equipment was prepared in step 100. Then the dry ingredientswere weighed and thereafter the liquid ingredients (steps 105 and 110).All weights for Examples 1-7 are shown below in Table III (by weight)and Table IV (by weight percent). Paste content for Example 7 wasestimated. Admixture amounts are fluid ounces per 100 lbs. ofcementitious material. Then in step 115, all of the LWA was placed intothe mixing pan 7 of a Hobart type pan mixer 6 (see FIG. 5B). This LWAwas composed of 3M brand S35 glass microspheres having a SG of about0.35, a median size of about 40 microns and a microsphere sizedistribution such that about 80% are between about 10-75 microns, andwith about a crushing strength 90% survival rate at about 3000 psi.Then, if the mix included an air entrainment admixture, the airentrainment admixture was added in step 120 together with about 80% ofthe water by weight to the lightweight aggregate in mixer 6. The airentrainment admixture was Euclid Chemical AEA-92. If the mix did not,about 80% of the water by weight was added in step 125 to thelightweight aggregate in mixer 6. In step 130, while adding water, mixer6 was run slowly at first, and then on full once enough of the water hadmixed with the LWA to reduce dust formation. Mixer 6 is then run untilstopped (step 135). Thereafter, the fibers were added to mixer 6 in step140. The fibers were NYCON brand PVA RECS15 8 mm fibers. Mixer 6 was runfor about a minute in step 145. As there is no sand or coarse aggregatesin these mixes, in step 160 the cementitious materials and remainingadmixtures (as listed on Table III) were added with the remaining (about20%) water. The cementitious materials were HOLCIM brand Type I/IIcement, BORAL brand Class F fly ash and EUCON brand MSA silica fume. Insteps 170 and 180, mixer 6 was run for about 3 minutes and thereafter,mixer 6 was stopped to permit the mix to rest for about 3 minutes. Whilemixer 6 was not running in step 190, mixer blades (paddles) 10 werecleaned off. Mixer 6 was run for about 2 minutes in step 200. At thispoint, the mix was tested in step 210 for compliance with target slumpand target measured air indicated in Table III as target values afterany adjustments, if any. If a mix did not comply, such mix was adjustedas required in step 220 to meet target slump and target measured air. Ifthe measured air was too high, de-air entrainment admixture was added instep. 225. If a mix was adjusted, then mixer 6 was run in step 230 forabout 2 minutes, and the mix was again tested (see step 210) forcompliance with target slump and target measured air. If it did notcomply, the steps above were repeated. If a mix did comply, then theprocess of preparing the batch, mixing the batched materials, andforming the wet concrete mix was complete (step 240).

TABLE III Mix/ Ex. B10 A2 B2 B3 B9 B10 SRA B12 SG 1 2 3 4 5 6 7 Material(lb./yd) Cement Holcim St. Gen 3.15 600 535 536 580 550 546 550 TypeI/II Fly Ash Boral Class F 2.49 139 140 105 125 124 125 Silica FumeEuclid Eucon MSA 2.29 60 22 22 18 18 17 18 Microspheres 3M microspheres,0.35 290.1 297.1 297.5 304.3 300 298.1 300 S35 Fiber Nycon PVA 1.01 6.75.95 5.96 6.8 6.8 6.7 6.8 RECS15 8 mm Water potable 1 519 476 477 457467 454 243 Admixtures (fl. oz./100 wt CM) Air Entrainer Euclid AEA-92 10.15 0.26 0.26 De-air BASF PS1390 1 5.96 10 Entrainer HRWRA Euclid SPC1.08 19.0 25.8 25.8 60.9 34.8 43.1 HRWRA BASF Glenium 1 34.4 7500Viscosity Euclid AWA 1 5.4 11.0 6.0 Modifier Viscosity Grace V-Mar 113.7 7.6 7.6 Modifier WRA/Retarder Euclid NR 1 4.9 Hydration EuclidStasis 1 2.0 2.0 2.0 2.0 2.0 Stabilizer Hydration BASF Delvo 1 2.0Stabilizer Shrinkage BASF MasterLife 1 37.0 Reducing SRA Latex BASFStyrofan 1.02 554.5 1186 Total Wt. (lb.) 1489 1494 1495 1508 1491 14881519 W/CM (not incl. water in 0.79 0.68 0.68 0.65 0.67 0.66 0.35Admixtures) Total (lb./yd) 660 696 697 703 693 688 693 CementitiousContent Paste Content (%, incl. air) 50.4 49.3 49.2 49.1 48.7 49.1 50 byVol. Replacement (%) 49.6 50.7 50.8 50.9 51.3 50.9 50 Volume

TABLE IV Mix/Ex. B10 A2 B2 B3 B9 B10 SRA B12 SG 1 2 3 4 5 6 7 Material(wt. %) Cement Holcim St. Gen 3.15 40.29 35.82 35.86 38.45 36.89 36.7136.20 Type I/II Fly Ash Boral Class F 2.49 9.31 9.37 6.96 8.38 8.34 8.23Silica Fume Euclid Eucon MSA 2.29 4.03 1.47 1.47 1.19 1.21 1.14 1.18Microspheres 3M microspheres, 0.35 19.48 19.89 19.90 20.17 20.12 20.0419.75 S35 Fiber Nycon PVA 1.01 .45 .40 .40 .45 .46 .45 .45 RECS15 8 mmWater potable 1 34.85 31.87 31.91 30.30 31.33 30.52 15.99 Admixtures(wt. %) Air Entrainer Euclid AEA-92 1 .0043 .0079 .0079 De-air BASFPS1390 1 .1806 .2974 Entrainer HRWRA Euclid SPC 1.08 .5930 .8465 .84831.999 1.139 1.402 HRWRA BASF Glenium 1 1.022 7500 Viscosity Euclid AWA 1.1560 .3342 .1827 Modifier Viscosity Grace V-Mar 1 .4163 .2303 .2289Modifier WRA/Retarder Euclid NR 1 .1416 Hydration Euclid Stasis 1 .0608.0609 .0608 .0606 .0602 Stabilizer Hydration BASF Delvo 1 .0595Stabilizer Shrinkage BASF MasterLife 1 1.1141 Reducing SRA Latex BASFStyrofan 1.02 16.82 1186

Following this, the fresh concrete properties were measured as describedabove: slump, plastic air content, temperature and plastic density. Themeasured values are provided in Table V below.

TABLE V Mix B10 A2 B2 B3 B9 B10 SRA B1 Ex. 1 2 3 4 5 6 7 Slump (in.)37.5 28 32.5 5.5 7 28.5 5.25 Plastic Air Content (%) 4.2 5.4 7.1 6.6 7 913 Temp. (F.) 73 76 76.2 73 76.1 80.5 78.2 Plastic Density (lb./cu. ft.)57 55.4 55 55 55.2 52.4 51.8

Thereafter, tests were conducted on the physical characteristics of theset concrete, as described above: compressive strength, elastic modulus,oven-dried density, bulk density and permeable porosity. The valuesmeasured are provided in Table VI and Table VII (value/density) below.

TABLE VI Mix B10 A2 B2 B3 B9 B10 SRA B1 Ex. 1 2 3 4 5 6 7 CompressiveResults Strength (psi) at day 3 1130 1687 1650 1627 4 1883 7 1583 25502180 2527 1880 1987 14 3020 2880 28 3310 2800 3960 3420 3387 2697Elastic Results Modulus (kpsi) at day 3 550 575 7 650 650 14 800 28 850800 900 800 825 Tensile Results Strength (psi) at day 3 232 243 7 300265 14 362 28 337 355 Modulus of 355 327 Rupture (psi) Oven Dried 40.739.3 40.8 40 40.5 40.5 Density (lb./cu. ft.) Ring Test 2.3 4.4 1.2(days) Bulk Density 62.9 59.5 (lb./cu. ft.) Permeable 34.9 32.1 Pores(%)

TABLE VII Mix B10 A2 B2 B3 B9 B10 SRA B1 Strength-to- Ex. density: 1 2 34 5 6 7 Compressive Strength Results at (cu. ft./sq. in.) day 3 28.841.3 41.3 40.2 4 46.3 7 40.3 62.5 54.5 62.4 46.4 14 74.2 72.0 28 81.371.2 97.1 85.5 83.6 Elastic Modulus (1000 s Results at (cu. ft./sq.in.)) day 3 13.75 14.20 7 16.25 16.05 14 20.00 28 20.88 20.36 22.0620.00 20.37 Tensile Strength Results at (cu. ft./sq. in.) day 3 5.806.00 7 7.50 6.54 14 9.05 28 8.43 8.77 Modulus of Rupture 8.88 8.07 (cu.ft./sq. in.)

Examples 8-12 Aggregate: SG 0.15 Microspheres

Concrete preparation and mixing was done in accordance with ASTM C192.The process is described in reference to FIGS. 3A-3B. First, allnecessary equipment was prepared in step 100. Then the dry ingredientswere weighed and thereafter, the liquid ingredients (steps 105 and 110).All weights for Examples 8-12 are shown below in Table VIII (by weight)and Table IX (by weight percent). Admixture amounts are fluid ounces per100 lbs. of cementitious material. Then in step 115 all of the LWA wasplaced into mixing pan 7 of a Hobart type pan mixer 6 (see FIG. 5B).This LWA was composed of 3M brand S15 glass microspheres having a SG ofabout 0.15, a median size of about 55 microns and a microsphere sizedistribution such that about 80% are between about 25-90 microns, andwith about a crushing strength 90% survival rate at about 300 psi. Then,if the mix included an air entrainment admixture, the air entrainmentadmixture was added in step 120 together with about 80% of the water byweight to the lightweight aggregate in mixer 6. The air entrainmentadmixture was Euclid Chemical AEA-92. If the mix did not, about 80% ofthe water by weight was added in step 125 to the lightweight aggregatein mixer 6. In step 130, while adding water, mixer 6 was run slowly atfirst, and then on full once enough of the water had mixed with the LWAto reduce dust formation. Mixer 6 is then run until stopped (step 135).Thereafter, the fibers were added to mixer 6 in step 140. The fiberswere NYCON brand PVA RECS15 8 mm fibers. Mixer 6 was run for about aminute in step 145. As there is no sand or coarse aggregates in thesemixes, in step 160 the cementitious materials and remaining admixtures(as listed on Table VIII) were added with the remaining (about 20%)water. The cementitious materials were HOLCIM brand Type I/II cement,BORAL brand Class F fly ash and EUCON brand MSA silica fume. In steps170 and 180, mixer 6 was run for about 3 minutes and thereafter, mixer 6was stopped to permit the mix to rest for about 3 minutes. While mixer 6was not running in step 190, the mixer blades (paddles) 10 were cleanedoff. Mixer 6 was run for about 2 minutes in step 200. At this point, themix was tested in step 210 for compliance with target slump and targetmeasured air indicated in Table VI as target values after anyadjustments, if any. If a mix did not comply, such mix was adjusted asrequired in step 200 to meet target slump and target measured air. Ifthe measured air was too high, de-air entrainment admixture was added instep 225. If a mix was adjusted, then mixer 6 was run in step 230 forabout 2 minutes, and the mix was again tested (see step 210) forcompliance with target slump and target measured air. If it did notcomply, the steps above were repeated. If a mix did comply, then theprocess of preparing the batch, mixing the batched materials and formingthe wet concrete mix was complete (step 240).

TABLE VIII Mix/Ex. C2 C3 C4 C5 C6 SG 8 9 10 11 12 Material (lb./yd)Cement Holcim St. Gen 3.15 585 573 615 638 750 Type I/II Fly Ash BoralClass F 2.49 152 149 160 123 75 Silica Fume Euclid Eucon MSA 2.29 24 2327 25 8 Microspheres 3M microspheres, 0.15 124.5 127.6 124.9 133 135 S15Fiber Nycon PVA 1.01 6.8 6.66 6.76 6.7 6.8 RECS15 8 mm Water potable 1474 458 454 475 454 Admixtures (fl. oz./100 wt CM) Air Entrainer EuclidAEA-92 1 0.26 0.26 0.18 HRWRA Euclid SPC 1.08 23.0 26.0 26.9 28.4 36.6Viscosity Modifier Grace V-Mar 1 6.0 6.0 8.0 10.0 8.0 HydrationStabilizer Euclid Stasis 1 2.0 2.0 2.0 2.0 2.0 Total Wt. (lb.) 1389 13551408 1423 1456 W/CM (not incl. water in 0.62 0.61 0.57 0.61 0.55Admixtures) Total Cementitious Content (lb./yd) 761 746 802 785 833Paste Content by Vol. (%, incl. air) 50.3 49.1 50.2 47 46.6 ReplacementVolume (%) 49.7 50.9 49.8 53 53.4

TABLE IX Mix/Ex. C2 C3 C4 C5 C6 SG 8 9 10 11 12 Material (wt. %) CementHolcim St. Gen 3.15 42.31 42.29 43.67 44.85 51.52 Type I/II Fly AshBoral Class F 2.49 10.99 11.00 11.36 8.65 5.15 Silica Fume Euclid EuconMSA 2.29 1.74 1.70 1.92 1.76 .55 Microspheres 3M microspheres, 0.15 9.009.42 8.87 9.35 9.27 S15 Fiber Nycon PVA 1.01 .49 .49 .48 .47 .47 RECS158 mm Water potable 1 34.28 33.80 32.24 33.39 31.19 Admixtures (wt. %)Air Entrainer Euclid AEA-92 1 .0093 .0093 .0067 .0000 .0000 HRWRA EuclidSPC 1.08 .891 1.007 1.079 1.106 1.475 Viscosity Modifier Grace V-Mar 1.2153 .2151 .2971 .3602 .2985 Hydration Stabilizer Euclid Stasis 1 .0718.0717 .0743 .0720 .0746

Following this, the fresh concrete properties were measured as describedabove: slump, plastic air content, temperature and plastic density. Thevalues measured are provided in Table X below.

TABLE X Mix C2 C3 C4 C5 C6 Ex. 8 9 10 11 12 Slump (in.) 6.5 28.5 25 3122.5 Plastic Air Content (%) 8.5 8 7 5.4 7 Temp. (F.) 72.5 71.6 76.2 74Plastic Density (lb./cu.ft.) 52.5 51.6 52.7 55.1 56

Thereafter, tests were conducted on the physical characteristics of theset concrete, as described above: compressive strength, elastic modulus,tensile strength, modulus of rupture, and oven-dried density. The valuesmeasured are provided in Table XI and Table XII (value/density) below.

TABLE XI Mix C2 C3 C4 C5 C6 Ex. 8 9 10 11 12 Compressive Results atStrength (psi) day 3 1100 1100 1270 1230 1740 7 1290 1400 1580 1540 193028 1770 1750 1920 1900 2140 Elastic Modulus Results at (kpsi) day 3 400400 500 450 550 7 500 500 550 550 600 28 600 550 650 650 700 TensileStrength Results at (psi) day 3 163 160 140 198 243 7 178 198 232 218242 28 260 237 257 293 295 Modulus of Rupture (psi) 300 270 300 350 310Oven Dried Density 36.5 36 39 40 42.5 (lb./cu. ft.)

TABLE XII Mix C2 C3 C4 C5 C6 Strength-to- Ex. density: 8 9 10 11 12Compressive Strength Results at (cu. ft./sq. in.) day 3 30.1 30.6 32.630.8 40.9 7 35.3 38.9 40.5 38.5 45.4 28 48.5 48.6 49.2 47.5 50.4 ElasticModulus (1000 s (cu. ft./ Results at sq. in.)) day 3 10.96 11.11 12.8211.25 12.94 7 13.70 13.89 14.10 13.75 14.12 28 16.44 15.28 16.67 16.2516.47 Tensile Strength Results at (cu. ft./sq. in.) day 3 4.47 4.44 3.594.95 5.72 7 4.88 5.50 5.95 5.45 5.69 28 7.12 6.58 6.59 7.33 6.94 Modulusof 8.22 7.50 7.69 8.75 7.29 Rupture (cu. ft./sq. in.)

Examples 13-17 Aggregate: SG 0.35/SG 0.15 Microspheres and Sand

Concrete preparation and mixing was done in accordance with ASTM C192.The process is described in reference to FIGS. 3A-3B. First, allnecessary equipment was prepared in step 100. Then the dry ingredientswere weighed and thereafter the liquid ingredients (steps 105 and 110).All weights for Examples 13-17 are shown below in Table XIII (by weight)and Table XIV (by weight percent). Admixture amounts are fluid ouncesper 100 lbs. of cementitious material. Then, in step 115, all of the LWAwas placed into mixing pan 7 of a Hobart type pan mixer 6 (see FIG. 5B).For Example 13, this LWA was composed of 3M brand S15 glass microsphereshaving a SG of about 0.15, a median size of about 55 microns and amicrosphere size distribution such that about 80% are between about25-90 microns, and with about a 90% crushing strength survival rate atabout 300 psi. For the remaining examples, this LWA was composed of 3Mbrand S35 glass microspheres having a SG of about 0.35, a median size ofabout 40 microns and a microsphere size distribution such that about 80%are between about 10-75 microns, and with about a crushing strength 90%survival rate at about 3000 psi. Then, if the mix included an airentrainment admixure, the air entrainment admixture was added in step120 together with about 80% of the water by weight to the lightweightaggregate in mixer 6. The air entrainment admixture was Euclid ChemicalAEA-92. If the mix did not, about 80% of the water by weight was addedin step 125 to the lightweight aggregate in mixer 6. In step 130, whileadding water, mixer 6 was run slowly at first, and then on full onceenough of the water had mixed with the LWA to reduce dust formation.Mixer 6 is then run until stopped (step 135). Thereafter, the fiberswere added to mixer 6 in step 140. The fibers were NYCON brand PVARECS15 8 mm fibers. Mixer 6 was run for about a minute in step 145.These mixes include sand but no coarse aggregates, so in step 150 thesand was added, followed by step 160, adding cementitious materials andremaining admixtures (as shown in Table XIII) with the remaining (about20%) water. The cementitious materials were HOLCIM brand Type I/IIcement, BORAL brand Class F fly ash and EUCON brand MSA silica fume. Theother aggregate was Meyer McHenry sand. In steps 170 and 180, mixer 6was run for about 3 minutes and thereafter, mixer 6 was stopped topermit the mix to rest for about 3 minutes. While mixer 6 was notrunning, in step 190, the mixer blades (paddles) 10 were cleaned off.Mixer 6 was run for about 2 minutes in step 200. At this point, the mixwas tested in step 210 for compliance with target slump and targetmeasured air indicated in Table IX as target values after anyadjustments, if any. If a mix did not comply, such mix was adjusted asrequired in step 220 to meet target slump and target measured air. Ifthe measured air was too high, de-air entrainment admixture was added instep. 225. If a mix was adjusted, then mixer 6 was run in step 230 forabout 2 minutes, and the mix was again tested (see step 210) forcompliance with target slump and target measured air. If it did notcomply, the steps above were repeated. If a mix did comply, then theprocess of preparing the batch, mixing the batched materials and formingthe wet concrete mix was complete (step 240).

TABLE XIII Mix/Ex. F1 G1 D1 E1 E2 SRA SRA Material (lb./yd) SG 13 14 1516 17 Cement Holcim St. Gen Type 3.15 611 611 611 611 626 I/II Fly AshBoral Class F 2.49 159 159 159 159 163 Silica Fume Euclid Eucon MSA 2.2927 27 27 27 27 Microspheres 3M microspheres, S15 0.15 98.8 Microspheres3M microspheres, S35 0.35 250.5 250.5 188 62.5 Sand Meyer McHenry 2.67485 333 333 927 2053 Fiber Nycon PVA RECS15 1.01 6.7 6.79 6.8 6.8 7 8 mmWater potable 1 450 461 454 385 314 Admixtures (fl. oz./100 wt CM) AirEntrainer Euclid AEA-92 0.18 0.18 HRWRA Euclid SPC 25.0 31.3 30.9 30.930.9 Viscosity Modifier Grace V-Mar 8.9 8.9 8.9 8.9 8.9 HydrationStabilizer Euclid Stasis 2.0 2.0 2.0 2.0 2.0 Shrinkage Reducing BASFMasterLife SRA 32.2 32.2 Admixtures (est. lbs./yd.) Total Wt. (lb.) 18571872 1864 2344 3293 W/CM (not incl. water in 0.57 0.58 0.57 0.48 0.38Admixtures) Total Cementitious (lb./yd) 796 796 796 796 816 ContentPaste Content by Vol. (%, incl. air) 49.8 50.6 50.2 47.1 43.4Replacement Volume (%) 39.35 42.07 42.41 32.13 10.67

TABLE XIV Mix/Ex. F1 G1 D1 E1 E2 SRA SRA (wt. %) SG 13 14 15 16 17Material Cement Holcim St. Gen 3.15 32.90 32.65 32.77 26.07 19.01 TypeI/II Fly Ash Boral Class F 2.49 8.56 8.50 8.53 6.78 4.95 Silica FumeEuclid Eucon MSA 2.29 1.45 1.44 1.45 1.15 .82 Microspheres 3Mmicrospheres, S15 0.15 5.32 Microspheres 3M microspheres, S35 0.35 13.3813.44 8.02 1.90 Sand Meyer McHenry 2.67 26.11 17.79 17.86 39.56 62.34Fiber Nycon PVA RECS15 1.01 .36 .36 .36 .29 .21 8 mm Water potable 124.23 24.63 24.35 16.43 9.53 Admixtures Air Entrainer Euclid AEA-92 1.0050 .0050 HRWRA Euclid SPC 1.08 .7554 .9386 .9302 .7400 .5391Viscosity Modifier Grace V-Mar 1 .2490 .2471 .2481 .1973 .1438 HydrationStabilizer Euclid Stasis 1 .0560 .0555 .0557 .0443 .0323 ShrinkageReducing BASF MasterLife SRA 1 .7140 .5202

Following this, the fresh concrete properties were measured as describedabove: slump, plastic air content, temperature and plastic density. Themeasured values are provided in Table X below.

TABLE XV Mix D1 E1 E2 F1 SRA G1 SRA Ex. 13 14 15 16 17 Slump (in.) 28.7527.75 31 30.5 23 Plastic Air Content (%) 4 6.8 6.2 5.9 6.5 Temp. (F.)74.4 76.3 73.5 77.1 75.4 Plastic Density (lb./cu.ft.) 73.7 68.8 68.387.6 124.9

Thereafter, tests were conducted on the physical characteristics of theset concrete, as described above: compressive strength, elastic modulus,tensile strength, modulus of rupture, and oven-dried density. The valuesmeasured are provided in Table XVI and Table XVII (value/density) below.

TABLE XVI Mix/Ex. F1 G1 Results D1 E1 E2 SRA SRA at day 13 14 15 16 17Compressive  3 1710 2200 2233 2370 3780 Strength (psi)  7 1890 2750 27572800 4390 10 3130 4780 28 2550 4000 4177 Elastic  3 650 850 750 Modulus 7 800 900 900 (kpsi) 10 1400 2900 28 950 1100 1100 Tensile  3 230 318293 Strength  7 242 365 288 (psi) 28 285 420 387 Modulus of 415 335 363Rupture (psi) Oven Dried Density 60 56.1 54.5 77.5 116.5 (lb./cu.ft.)Ring Test (days) 1.5

TABLE XVII Mix/Ex. Results F1 G1 Strength-to- at D1 E1 E2 SRA SRAdensity: day 13 14 15 16 17 Compressive  3 28.5 39.2 41.0 30.6 32.4Strength  7 31.5 49.0 50.6 36.1 37.7 (cu.ft./sq.in.) 10 40.4 41.0 2842.5 71.3 76.6 Elastic Modulus  3 10.83 15.15 13.76 (1000 s  7 13.3316.04 16.51 (cu.ft./sq.in.)) 10 18.06 24.89 28 15.83 19.61 20.18 TensileStrength  3 3.83 5.67 5.38 (cu.ft./sq.in.)  7 4.03 6.51 5.28 28 4.757.49 7.10 Modulus of 6.92 5.97 6.66 Rupture (cu.ft./sq.in.)

Examples 18-22 Aggregate: SG 0.35 Microspheres and Coarse Aggregate,With or Without Sand

Concrete preparation and mixing was done in accordance with ASTM C192.The process is described in reference to FIGS. 3A-3B. First, allnecessary equipment was prepared in step 100. Then the dry ingredientswere weighed and thereafter the liquid ingredients (steps 105 and 110).All weights for Examples 18-22 are shown below in Table XVIII (byweight) and Table XIX (by weight percent). Admixture amounts are fluidounces per 100 lbs. of cementitious material. Then, in step 115, all ofthe LWA was placed into mixing pan 7 of a Hobart type pan mixer 6 (seeFIG. 5B). This LWA was composed of 3M brand S35 glass microsphereshaving a SG of about 0.35, a median size of about 40 microns, and amicrosphere size distribution such that about 80% are between about10-75 microns, and with about a crushing strength 90% survival rate atabout 3000 psi. Then, about 80% of the water by weight was added in step125 to the lightweight aggregate in mixer 6. In step 130, while addingwater, mixer 6 was run slowly at first, and then on full once enough ofthe water had mixed with the LWA to reduce dust formation. Mixer 6 isthen run until stopped (step 135). Thereafter, the fibers were added tomixer 6 in step 140. The fibers were NYCON brand PVA RECS15 8 mm fibers.Mixer 6 was run for about a minute in step 145. These mixes includecoarse aggregates and some include sand, so in step 150 the sand wasadded if in the mix design, and in step 155 the coarse aggregate wasadded, followed by step 160, adding cementitious materials and remainingadmixtures (as shown in Table XVIII) with the remaining (about 20%)water. The cementitious materials were HOLCIM brand Type I/II cement,BORAL brand Class F fly ash and EUCON brand MSA silica fume. The otheraggregates were Meyer McHenry sand and Vulcan McCook CM-11 and MartinMarietta #8 coarse aggregates. In steps 170 and 180, mixer 6 was run forabout 3 minutes and thereafter, mixer 6 was stopped to permit the mix torest for about 3 minutes. While mixer 6 was not running, in step 190,the mixer blades (paddles) 10 were cleaned off. Mixer 6 was run forabout 2 minutes in step 200. At this point, the mix was tested in step210 for compliance with target slump and target measured air indicatedin Table XII as target values after any adjustments, if any. If a mixdid not comply, such mix was adjusted as required in step 220 to meettarget slump and target measured air. If the measured air was too high,de-air entrainment admixture was added in step 225. If a mix wasadjusted, then mixer 6 was run in step 230 for about 2 minutes, and themix was again tested (see step 210) for compliance with target slump andtarget measured air. If it did not comply, the steps above wererepeated. If a mix did comply, then the process of preparing the batch,mixing the batched materials and forming the wet concrete mix wascomplete (step 240).

TABLE XVIII Mix/Ex. F9 G4 G5 H1 SRA SRA G4 SRA SRA SG 18 19 20 21 22Material (lb./yd) Cement Holcim St. Gen Type I/II 3.15 615 611 618 634620 Fly Ash Boral Class F 2.49 154 159 161 159 155 Silica Fume EuclidEUCON MSA 2.29 27 27 Microspheres 3M microspheres, S35 0.35 219.5 100101.2 100.6 186.5 Coarse Aggregate Vulcan McCook CM-11 2.69 1440 14571491 Coarse Aggregate Martin Marietta #8 2.64 904 1378 Sand MeyerMcHenry 2.67 575 582 595 Fiber Nycon PVA RECS15 8 mm 1.01 6.63 6.8 6.96.83 6.68 Water potable 1 328 265 266 257 259 Admixtures (fl.oz./100 wtCM) De-Air Entrainer BASF PS 1390 10 10 10 10 HRWRA BASF Glenium 750030.0 30.9 30.0 30.0 30.0 Viscosity Modifier Grace V-MAR 8.9 8.9Viscosity Modifier BASF MasterMatrix 10.0 8.0 8.0 VMA 362 HydrationStabilizer BASF Delvo 2.0 2.0 2.0 2.0 1.0 Shrinkage Reducing BASFMasterLife SRA 20 48.8 32.2 32.5 48.8 Total Wt. (lb.) 2278 3227 32463281 2655 W/CM (not incl. water in 0.43 0.33 0.33 0.32 0.33 Admixtures)Total Cementitious (lb./yd) 769 796 805 793 775 Content Paste Content byVol. (%, incl. air) 43.1 38.5 37.8 36.9 38 Replacement Volume (%) 36.817.0 17.1 17.0 31.3

TABLE XIX Mix/Ex. F9 G4 G5 H1 SRA SRA G4 SRA SRA SG 18 19 20 21 22Material (lb./yd) Cement Holcim St. Gen Type I/II 3.15 27.00 18.93 19.0419.32 23.36 Fly Ash MRT Labadie Class C 2.75 6.76 4.93 4.96 4.85 5.84Silica Fume Euclid EUCON MSA 2.29 .84 .83 Microspheres 3M microspheres,S35 0.35 9.64 3.10 3.12 3.07 7.03 Coarse Aggregate Vulcan McCook CM-112.69 44.62 44.89 45.44 Coarse Aggregate Martin Marietta #8 2.64 39.6951.91 Sand Meyer McHenry 2.67 17.82 17.93 18.14 Fiber Nycon PVA RECS151.01 .29 .21 .21 .21 .25 8 mm Water potable 1 14.40 8.21 8.20 7.83 9.76Admixtures (wt. %) De-Air Entrainer BASF PS 1390 1 .2201 .1610 .1619.1903 HRWRA BASF Glenium 7500 1 .6604 .4975 .4857 .4728 .5710 ViscosityModifier Grace V-MAR 1 .1433 .1441 Viscosity Modifier BASF MasterMatrix1 .2201 .1261 .1523 VMA 362 Hydration Stabilizer BASF Delvo 1 .0440.0322 .0324 .0315 .0190 Shrinkage Reducing BASF MasterLife SRA 20 11.074 .518 .512 .929

Following this, the fresh concrete properties were measured as describedabove: slump, plastic air content, temperature and plastic density. Themeasured values are provided in Table XX below.

TABLE XX Mix F9 SRA G4 SRA G4 G5 SRA H1 SRA Ex. 18 19 20 21 22 Slump(in.) 6.5 20.25 20.25 22.75 22.75 Plastic Air 6.3 2.4 2.8 4.35 5.65Content (%) Temp. (F.) 80.1 78.4 76.8 78.3 84.5 Plastic Density 85.8128.4 129 126.5 100.1 (lb./cu.ft.)

Thereafter, tests were conducted on the physical characteristics of theset concrete, as described above: compressive strength, elastic modulus,tensile strength, modulus of rupture, and oven-dried density. Themeasured values are provided in Table XXI and Table XXII (value/density)below.

TABLE XXI Mix/Ex. F9 G4 G5 H1 Results SRA SRA G4 SRA SRA at day 18 19 2021 22 Compressive  3 2867 4440 5040 5127 3983 Strength (psi)  7 31975160 5595 6097 4690 28 3830 7060 5157 Elastic  3 1350 3375 2150 Modulus 7 1425 3350 3450 3625 2300 (kpsi) 28 1625 4175 2450 Tensile  3 308 533420 Strength  7 333 638 460 (psi) 28 417 625 478 Modulus of 450 608 908Rupture (psi) Oven Dried 78.5 120 120.5 121.5 99.5 Density (lb./cu.ft.)Chloride ion 196 283 133 penetrability (coulumbs, 28 d) Abrasion 0.0360.032 0.032 resistance (in. 28 d) Ring test (days) 11.1 17.4 10.5 16.210.1 CTE (in./in./F) 5.70E−006

TABLE XXII Mix/Ex. Results F9 G4 G5 H1 Strength-to- at SRA SRA G4 SRASRA density day 18 19 20 21 22 Compressive  3 36.5 37.0 41.8 42.2 40.0Strength  7 40.7 43.0 46.4 50.2 47.1 (cu.ft./sq.in.) 28 48.8 58.1 51.8Elastic Modulus  3 17.20 27.78 21.61 (1000 s  7 18.15 27.92 28.63 29.8423.12 (cu.ft./sq.in.)) 28 20.70 34.36 24.62 Tensile Strength  3 3.924.39 4.22 (cu.ft./sq.in.)  7 4.24 5.25 4.62 28 5.31 5.14 4.80 Modulus of5.73 5.00 9.13 Rupture (cu.ft./sq.in.)

Some examples included shrinkage reducing admixtures, which may reducestrength by about 10%. Accordingly, based upon predictions relying uponthe experimentally-determined values, one may estimate a range ofcompressive strength values expected for a variety of concrete mixesthat may or may not include such an admixture. These are found in TableXXIII below.

TABLE XXIII Mix density 28-day compressive (lb./cu.ft.) strength (psi)40 3200-3800 60 3800-4600 75 3955-4770 90 5990-7009 110 7800-9000

An embodiment of the invention may be prepared as a dry mix, such as fora bagged concrete mix. A bagging facility acquires bags and concreteprecursor materials including cementitious materials, aggregates, dryadmixtures, and reinforcing materials. Materials may be purchased orextracted. The precursor materials are prepared, including with anypre-mixing such as of dry admixtures. The precursor materials areblended in a continuous process. The dry mix is then bagged. As shown inFIG. 4, these steps include steps 300 and 310, acquire bags and anynecessary Portland cement, class F fly ash, silica fume, sand, glassmicrospheres, dry admixtures, and reinforcing materials. If necessary,step 320 is to prepare cementitious materials, aggregates, dryadmixtures, and reinforcing materials for blending. In step 325, carryout any necessary pre-mixing of the acquire materials. In step 330,blend all necessary materials in a continuous process. In step 340,place blended dry mix into bags, and 350 seal the bags.

Different technologies are available for mixing concrete. In all cases,a concrete mixer (or sometimes, “cement mixer”) is a device thathomogeneously combines the materials being mixed, such as cementitiousmaterials, aggregate, water, and any other additives or reinforcingmaterials, to form a concrete mix. In embodiments of the invention,there are both stationary and mobile concrete mixers.

Turning to FIGS. 5A-5B, among the former, there are twin-shaft mixers,vertical axis mixers, which includes both pan mixers 6 and planetary (orcounter-current) mixers, and which typically is used for batches betweenabout 1-4 cu.yd., and drum mixers 12 (which includes both reversing drummixers and tilting drum mixers). Drum mixers are suitable for the readymix market as they are capable of high production speeds and are capableof producing in large volumes (batches between about 4-12 cu.yd. ormore). All such mixers are charged for a batch of concrete by pouringthe dry and wet components into the pan 7 or drum 13, either while it isstationary or in motion, and in a sequence determined by the concretedesign. A motor 8, typically electric or gas/diesel-powered, drives ashaft 9 which directly or indirectly rotates and mixes the concrete mix,typically by paddle 10 or by friction and the material being carriedalong by the drum or by screw 14 in a drum mixer. In the case of drummixers, as shown in FIG. 5D, the mixed concrete is mixed by truck 15,and delivered, in the same manner as with stationary mixers. Batchplants are example of a drum mixer that is stationary, althoughcomponents of the plant may be tractor-trailer mounted, transported to alocation and assembled for use, and then disassembled and moved.

Turning to FIG. 5C, another form of stationary mixer is the ribbon mixer27 having hopper 28, outlet 29, body 30, blade assembly 31, ribbon blade32, shaft 33 and supports 34. Blade assembly 31 is driven by driver 35(typically electric or gas/diesel-powered) via shaft 33. Such a mixer ischarged by pouring the dry and wet components into the hopper 28, eitherwhile blade assembly 31 is stationary or in motion, and in a sequencedetermined by the concrete design. Rotation of blade assembly 31 andthereby ribbon blade 32, causes mixing of the charged materials.

The latter (mobile mixers) includes concrete transport trucks(“cement-mixers” or “in-transit mixers”) as shown in FIG. 5D for mixingconcrete and transporting it to the construction site. In embodiments ofthe invention, such trucks 15 have a powered rotating drum 13 theinterior of which has a spiral blade 14. Rotating drum 13 in onedirection pushes the concrete deeper into drum 13. Drum 13 is rotated inthis (the “charging”) direction while truck 15 is being charged withconcrete, and while the concrete is being transported to the buildingsite. Rotating drum 13 in the other (the “discharge”) direction causesthe Archimedes screw-type arrangement to discharge or force the concreteout of drum 13 onto chute 16.

Examples of other mixers include: concrete mixing trailer, portablemixers, metered concrete trucks (containing weighed and loaded butunmixed components for mixing and use on-site), V blender, continuousprocessor, cone screw blenders, screw blenders, double cone blenders,planetary mixers, double planetary, high viscosity mixers,counter-rotating, double and triple shaft, vacuum mixers, high shearrotor stator, dispersion mixers, paddle mixers, jet mixers, mobilemixers, Banbury mixers, and intermix mixers.

In embodiments of the invention, there are two modes of use of aconcrete mixing truck: dry-charge-and-transport and pre-mixed transport.In the first mode, truck 15 is charged from a batch plant with theas-yet unmixed components of a concrete mix, including dry materials,water and other additives and/or reinforcements, in a sequencedetermined by the concrete design, with the rotation of drum 13 mixingthe concrete during transport to the destination. In the second mode,truck 15 is charged from a batch plant at a concrete manufacturing plant(or “central mix” plant), with a concrete mix that has already had thedry materials, water and other additives and/or reinforcements added ina sequence determined by the concrete design, and already mixed beforeloading. In this case, rotation of drum 13 mixing the concrete duringtransport to the destination maintains the mix's liquid state untildelivery.

Once at the delivery or construction site, drum 13 is operated in thedischarge direction to force the wet mix onto chutes 16 used to guidethe mix directly to the job site. In this case, the job site may includeother machines used to move or process the wet mix, such as a concreteplacer or paving machine. If the use of chute 16 does not permit theconcrete to reach the necessary location, concrete may be dischargedinto a concrete pump, connected to a flexible hose, or onto a conveyorbelt which can be extended some distance (typically ten or more meters).A pump provides the means to move the material to precise locations,multi-floor buildings, and other distance prohibitive locations.Examples of pumps include a mobile concrete pump, which accepts forinstance ready mix concrete, delivered by dump truck or concrete mixingtruck. Such a mobile pump can place concrete at the desired positionduring the construction process using a pipe mounted on a movable boom.Another example is a stationary concrete pump, which operates similarlyexcept that the pipe is stationary and mounted primarily vertically upthe side of a structure during the construction process to provideconcrete at the desired location.

Embodiments of the present invention include different processes forpreparing and supplying concrete for end use.

In one embodiment, a central-mix facility may prepare and mix theconcrete itself. This mix process is described in reference to FIG. 6.Step 400 is acquiring concrete precursor materials including water,cementitious materials, aggregates (including LWAs, sand and gravel),admixtures, and reinforcing materials. This may be done, for example, bypurchase or extraction. In step 405, if necessary, the acquiredmaterials are prepared, including any premixing. The individualmaterials are measured, step 420, typically by weight or volume and, instep 430, formed into batches of individual components. The concreteprecursor materials are charged into a concrete mixer (dry, step 440,and water, step 450), typically a drum type, and mixed by operating thedrum in step 460. The resultant wet mix may be either used for charging,in step 470, a concrete mixing truck or dump truck, or used on-site, instep 480, by discharging it into a pump or delivery apparatus. Aconcrete mixing truck 15 or dump truck may be owned or controlled by thecentral-mix facility or by a third-party. Such a third-party may be abuilder or general contractor, or a contractor supplying such a party.In embodiments of the present invention, use on-site may includemachinery to place the concrete mix for a structure or building or useof the mix for pre-casting. In embodiments of the invention, on-site useincludes forming structural beams, architectural panels, sound barriers,blast walls, stadium seating, trench backfill around piping/conduit,insulated roofing, walls, tilt-wall panels, buildings, communicationtower buildings, and many other uses typical of normal concrete.

In one embodiment, a central-mix facility prepares the concreteprecursor materials but delivers or provides those materials to anotherparty for mixing. This mix process is also described in reference toFIG. 6. Step 400 is acquiring concrete precursor materials includingwater, cementitious materials, aggregates (including LWAs, sand andgravel), admixtures, and reinforcing materials. This may be done, forexample, by purchase or extraction. In step 405, if necessary, theacquired materials are prepared, including any premixing. The individualmaterials are measured, step 420, typically by weight or volume, in step430, and formed into batches of individual components. The concreteprecursor materials are then used for charging a concrete mixing truck(dry, step 490, and water, step 500), or pre-measured bags. A concretemixing truck then performs the mixing of the concrete in step 510, anddelivers and discharges it as required in steps 520 and 530. Deliverymay include to the site of a building or other structure underconstruction. Such a concrete mixing truck may be owned or controlledby, for instance, a builder or general contractor, or a contractorsupplying such a party.

Turning to FIGS. 7A-7B, precast concrete is a construction productproduced by casting concrete in a reusable mold 20 or “form,” curing itin a controlled environment, transporting to the construction site andplacing the precast item 21 where needed. This is in contrast tostandard concrete manufacturing in which the wet mix is poured intosite-specific forms 22 in-place and cured in-place to create an item 21.Pre-casting may also involve casting concrete in a reusable mold 20on-site, curing it in a controlled environment, and transporting itwithin the construction site to where it is needed. In embodiments ofthe invention, items 21 made by pre-casting include but are not limitedto concrete blocks, structural beams, double-tees, architectural panels,sound barriers, blast walls, tilt-wall panels, electric and light poles,bridge deck panels, fire-proofing, fencing, cement board, concreteroofing tiles, and floating platforms.

Concrete is highly resistant to fire and high heat if properly appliedand cured; it is non-combustible at the temperatures reached in ordinarystructural or even industrial fires. In one embodiment of the invention,an uncured composition may be applied to a structure or material asfire-proofing, either by troweling or spraying the composition onto thestructure or material, and allowed to cure. In this case a desired slumpis low slump. In another embodiment, an uncured composition may beformed around a structure, structural element, or material asfire-proofing, in which a steel structural element (e.g. a beam) isplaced partly within a mold (or the mold placed around it), the moldfilled with the composition (as disclosed herein) and allowed to cure.These processes can occur in-situ or elsewhere, such as a precastingfacility.

In one embodiment of the invention, precast (or “dry cast”) manufactureof products, including concrete blocks, involves providing extremelylow-slump concrete (almost zero), with a low W/CM ratio (about 0.22 orlower). LWC mixes described herein that do not include coarse aggregatewould be expected to be acceptable for making concrete blocks, with themodifications of removing admixtures and reducing water to form toextremely low-slump concrete (almost zero), with a low W/CM ratio (about0.22). Mixes including polymer or copolymer beads, or polymer orcopolymer beads with glass microspheres, may be acceptable, and are alsodisclosed. An admixture could be used as a wetting agent for formremoval.

The mixing process steps are, as shown in FIG. 8A and with reference toFIG. 5C, is to first prepare equipment in step 600, and then, in steps605 and 610, weigh any dry ingredients and liquid ingredients. In step615, place all lightweight aggregate into hopper 28 of ribbon mixer 27,while it is running. Other mixers may be acceptable. Then, in steps 620and 625, place all cement and all water into hopper 28 of ribbon mixer27, while it is running. Then, in step 630, run ribbon mixer 27 forabout an additional minute.

For concrete blocks, as shown in FIG. 8A and with reference to FIG. 8B,the LWC mix may be conveyed to block machine 40 at a measured flow ratein step 635 and placed into a reusable mold 41 for a concrete block instep 640. Mold 41 includes outer mold box 42 into which the LWC mix isplace and one or more mold liners 43. Liners 43 determine the outershape of the block and the inner shape of the block cavities. Such moldsmay be used for form different sizes and shapes of concrete blocks, suchas those having 4″, 8″ or 12″ thickness, or having two or three “cores”44 (i.e. the hollow portion) or no core (i.e. solid blocks). Said shapesneed not be rectangular, and can be curved or irregular, and liner 43may form one block or multiple blocks having the same shape or havingshapes differing from one another in the same liner. If required, instep 645, one or more mold liners 43 are inserted into the LWC mixinside of outer mold box 42 to form cores 44. In step 650, the concretemix in mold 41 is subjected to high compression and vibration. However,the vibration required may be lower than ordinary concrete mixes. Due tothe low slump, compression and vibration, and aided by the low density(that is, the reduced per-block mass), block 45 is quickly able to standunsupported. Following sufficient compression and vibration mold 41 isremoved (or stripped) by withdrawing mold liners 43 (if required, instep 655) and removing outer mold box 42 in step 660. Blocks 45 arepushed down and out of the molds. And block 45 is then set aside forcuring in step 665, following which the block may be transported to aconstruction site or sold for further sale. Curing may includesteam-curing, moisture-curing or other processes to develop desirableconcrete properties. Reducing the per-block mass may reduce themanufacturing time by reducing the time required for compression andvibration, and the time before forms can be removed.

Example 23, and test results for compressive strength, and exemplaryranges in Example 24 of such a concrete are shown in Table XXIV:

TABLE XXIV Mix/Ex. CMU Rng. Material (lb./yd) SG 23 24 Cement Holcim St.Gen 3.15 717 400-800 Type I/II Fly Ash 2.75 (cement range value includesfly ash) Microspheres 3M microspheres, 0.15 124.5  90-140 S15  0-50Microspheres 0.10-0.50  0-100 100-200 Sand Meyer McHenry 2.67 200-450Water potable 1   158 (see W/CM) W/CM — 0.22 0.15-0.35 Compressive14-day 1030  500-3000 Strength (psi)

The structural concrete blocks made met or exceeded design strengths.

Values for R-value (a measure of the insulating effect of a material)were established by testing thermal conductivity of two specimens of aLWC per ASTM C177. The specimens were formed from a LWC mix according toExample 5. The specimens were (L/W/T in in.) 11.97×12.04×2.05 and11.93×12.03×2.04, and had, respectively a dry density (in lb/cu.ft.) of41.0 and 40.9. Thermal conductivity C_(T) (in (Btu-in.)/(hr-°F.-sq.ft))was 1.15. Calculated R-value results are presented below in Table XXV.

TABLE XXV Thickness (in.) 1.0 2.0 3.0 4.0 5.0 6.0 9.0 12.0 R-value 0.871.74 2.61 3.49 4.36 5.23 7.84 10.46

A LWA of an embodiment of the invention may also comprise small beadsformed of a plastic, such as a copolymer. These polymer beads may haveroughly the density of water, are typically solid, closed, preferablyinsoluble, non-porous, substantially resistant to volumetric changeunder pressure, heat-resistant, smooth and non-absorptive.

The polymer beads made be composed of a polymeric material, such aspolymers of styrene, ethylinylbenzene, divinylbenzene or any combinationof any of the foregoing. For example, the beads may be made ofcopolymers such as styrene copolymers andstyrene-ethylvinylbenzene-divinylbenzene terpolymers.

Suitable beads include those described in U.S. Patent Publication No.2015/0011439 (also published as U.S. Pat. Nos. 8,466,093, 8,278,873,8,455,403, 8,088,718, 702,125, and 7,803,740), each of which is herebyincorporated by reference. In one embodiment, the polymeric beads arepolymeric nanocomposite spherical beads such as those described in U.S.Patent Publication No. 2015/0011439. The polymer nanocomposite sphericalbeads may comprise a polymer matrix (such as a rigid thermoset polymer)and nanofiller particles. In one embodiment, the polymer matrix is athermoset polymer matrix, such as astyrene-ethylvinylbenzene-divinylbenzene terpolymer. The nanofillerparticles are preferably dispersed throughout the bead. Suitablenanofiller particles include, but are not limited to, carbon black,fumed silica, fumed alumina, carbon nanotubes, carbon nanofibers,cellulosic nanofibers, fly ash, polyhedral oligomeric silsesquioxanes,natural nanoclays, synthetic nanoclays any combination of any of theforegoing. The beads may include 0.001 to 60 volume percent ofnanofiller particles.

In one preferred embodiment, the polymeric beads have a specific gravityof about 1 or greater, for example, a specific gravity of from about 1to about 1.5 or from about 1 to about 1.2. Examples of suitablepolymeric beads include, but are not limited to, Alpine drilling beadsavailable from Alpine Specialty Chemicals of Houston, Tex., and SunLubra-Glide beads (available from Sun Drilling Products Corp. of BelieChasse, La.) and any combination of the foregoing. In one embodiment,the beads have a diameter ranging from 0.1 mm to 4 mm.

In addition, polymer beads may have a rough or irregular surface, or beirregular in shape. Commercial polymer beads are typically smooth, butthe surface could be etched, such as by acid-washing or other methods.Without being bound by any particular theory, it is believed thatetching may permit better adhesion between the cementitious materialsand the polymer beads, leading to greater strength. Doing so may alsopermit or encourage reaction between the polymer beads and thecementitious materials.

An embodiment of the present invention includes anoptionally-self-compacting LWC mix having a low weight-fraction ofaggregate to total dry raw materials, and highly-homogenous mixproperties. That LWC mix includes a LWA that is composed of polymerbeads, as described above.

The polymer beads may be in more than one size. These include both fineor coarse sizes. In the fine size, the polymer beads may have a medianparticle size of, as an example, about 100-500 microns. The median sizemay be about 300 microns, greater than about 150 microns, and greaterthan about 250 microns but less than about 350 microns. In oneembodiment, substantially all of the polymer beads have a particle sizebetween about 100-500 microns. In the coarse size, the polymer beads mayhave a median particle size of, as an example, about 350-1000 microns.The median size may be about 675 microns, greater than about 500microns, and greater than about 650 microns but less than about 750microns. In one embodiment, substantially all of the polymer beads havea particle size between about 350-1000 microns. The polymer beads'median size may be substantially greater than that of the microspheres.

In density, the polymer beads (and the polymer forming them) may rangebetween around 0.8 and about 1.4 SG, between around 1 and about 1.5 SG,or as low as between about 0.6-0.9, or between about 0.95-1.15, orbetween about 1.02-1.15, with exemplary densities of 0.9, 1.06, 1.10 and1.2 SG. In a preferred embodiment, the beads have about neutral buoyancyrelative to water. Such polymer beads can remain stable at temperaturesup to 425° F., 450° F., or even 525° F. Such polymer beads may resistdeformation at over about 15,000, 20,000 and 25,000 psi hydrostaticpressure.

In one embodiment, the LWC and LWC mixes include the polymer beadsdisclosed above as the LWA either as the sole LWA or in conjunction withother forms of LWA as described herein (for example 3M brand S15 glassmicrospheres having a SG of about 0.15, or 3M brand S35 glassmicrospheres having a SG of about 0.35 and other microspheres includingthose disclosed herein having other densities), and may in additioninclude ordinary aggregates, including both sand and/or gravel. Thepolymer bead and glass microsphere varieties of LWA may compose all ofthe LWA in the LWC or LWC mix or may compose all of the aggregate mix.In compositions having target oven-dried densities below 55 lbs./cu.ft.,it is expected that polymer beads would be combined with one or moretype of glass microspheres to meet that low density.

In embodiments in which polymer beads are not used in conjunction withother forms of LWA, their weight percentage of the composition may rangefrom about 20% or below, to over 75%, with particular embodimentsincluding weight percentages of about: 30%, 50%, 65%, and 70%, andranges including from about 20-30%, about 45-55%, and about 60-75%. Inembodiments in which polymer beads are used in conjunction with ordinaryaggregate, their weight percentage of the composition may range fromabout 5% or below, to over 50%, with particular embodiments includingweight percentages of about: 10%, 20%, 40%, and 50%, and rangesincluding from about 5-15%, about 15-25%, and about 35-45%.

In embodiments in which polymer beads are used in conjunction with otherforms of LWA, the polymer beads' median size may be substantiallygreater than the other LWA. In one embodiment, the LWA includes polymerbeads and glass microspheres where the ratio of the median sizes of thepolymer beads and the glass microspheres is at least about 3; in othersit is at least about 4, 5, 8 10, 12 and 15.

In embodiments in which polymer beads are used in conjunction with otherforms of LWA, the LWA includes polymer beads and glass microsphereswhere the ratio of the weights (or equivalently the weight percentages)of the polymer beads to that of the glass microspheres may be betweenabout 0.3-6, about 0.5, about 1, about 4, about 3.25, ranges of about3-4, about 2-5, and about 6-9.

In embodiments in which polymer beads are used in conjunction with glassmicrospheres, the ratio of the volume of the glass microspheres to thatof the polymer beads may be between about 0.3-6, about 0.5, about 1,about 1.5, about 2, about 4 and about 6, ranges of about 0.5-2, andabout 2-5. Without being bound by any particular theory, in suchembodiments, it is theorized that replacing smaller LWA (such as theglass microspheres) with the polymer beads will reduce the W/CM rationecessary to form a workable composition. It is believed that this isbecause an equivalent volume of polymer beads has a lower surface area,requiring less water to create the cement paste necessary to coat thatsurface.

An advantage of LWC mixes using polymer beads as the LWA (either solelyor in conjunction with other forms of LWA as described herein) is thathaving an SG close to that of water reduces their tendency to segregate.Using polymer beads as the LWA may also reduce or eliminate thesegregation of mix components by density. By reducing or eliminatingsegregation, one may reduce or eliminate the use of viscosity modifieradmixtures designed to alter the mix viscosity. It is expected thatviscosity modifier admixtures may still be important or necessary ifglass microsphere LWA is used with polymer beads.

Examples 25-31 (Prophetic) Aggregate: SG 1.06 Polymer Beads With orWithout SG 0.15 Microspheres, and With or Without Sand or CoarseAggregate

Concrete preparation and mixing are done in accordance with ASTM C192.The process is described in reference to FIGS. 3A-3B. First, allnecessary equipment are prepared in step 100. Then the dry ingredientsare weighed and thereafter the liquid ingredients (steps 105 and 110).All weights for Examples 25-31 are shown below in Table XXVI (by weight)and Table XXVII (by weight percent). Admixture amounts would be fluidounces per 100 lbs. of cementitious material. Admixtures may be any ofthose previously discussed, and in the disclosed amounts, including ashrinkage reducing admixture including an expansive agent but are notset out in the Tables. Then, in step 115, all of the LWA is placed intomixing pan 7 of a Hobart type pan mixer 6 (see FIG. 5B). This LWA iscomposed of polymer beads made of a copolymer having an SG of about1.06. Either fine or coarse polymer beads could be used, and in someinstances additional LWA composed of 3M brand S15 glass microsphereshaving a SG of about 0.15, a median size of about 55 microns and amicrosphere size distribution such that about 80% are between about25-90 microns, and with about a crushing strength 90% survival rate atabout 300 psi. Other forms/sizes of microsphere LWA could be used. Then,about 80% of the water by weight is added in step 125 to the lightweightaggregate in mixer 6. In step 130, while adding water, mixer 6 is runslowly at first, and then on full once enough of the water had mixedwith the LWA to reduce dust formation. Mixer 6 is then run until stopped(step 135). Thereafter, if utilized, the fibers are added to mixer 6 instep 140. The fibers could be NYCON brand PVA RECS15 8 mm fibers. Mixer6 is run for about a minute in step 145. Such mixes may include coarseaggregates and may include sand, so in step 150 the sand is added if inthe mix design, and in step 155 the coarse aggregate was added if in themix design, followed by step 160, adding cementitious materials andremaining admixtures (as shown in Table XXVI) with the remaining (about20%) water. The cementitious materials are HOLCIM brand Type I/IIcement, and if present, could be BORAL brand Class F fly ash and EUCONbrand MSA silica fume. The other aggregates, if present, could be MeyerMcHenry sand and either Vulcan McCook CM-11 or Martin Marietta #8 coarseaggregates. In steps 170 and 180, mixer 6 is run for about 3 minutes andthereafter, mixer 6 was stopped to permit the mix to rest for about 3minutes. While mixer 6 was not running, in step 190, the mixer blades(paddles) 10 are cleaned off. Mixer 6 is run for about 2 minutes in step200. At this point, the mix is tested in step 210 for compliance withtarget slump and target measured air indicated in Table XII as targetvalues after any adjustments, if any. Target measured air (plastic air)in each instance is 5%. If a mix does not comply, such mix is adjustedas required in step 220 to meet target slump and target measured air. Ifthe measured air is too high, de-air entrainment admixture was added instep 225. If a mix is adjusted, then mixer 6 is run in step 230 forabout 2 minutes, and the mix is again tested (see step 210) forcompliance with target slump and target measured air. If it does notcomply, the steps above are repeated. If a mix does comply, then theprocess of preparing the batch, mixing the batched materials and formingthe wet concrete mix is complete (step 240).

TABLE XXVI Ex. SG 25 26 27 28 29 30 31 Material (lb./yd) Cement HolcimSt. Gen 3.15 675 675 611 500 470 564 564 Type I/II Polymer beadsCopolymer beads 1.06 1112 1150 1200 1342 1403 400 400 Microspheres 3Mmicrospheres, 0.15 114 123 S15 Water potable 1 338 304 275 175 188 282226 Total Wt. (lb.) 2125 2529 2086 2017 2061 1360 1313 W/CM (not incl.water in 0.5 0.45 0.45 0.35 0.4 0.5 0.4 Admixtures) Plastic Densitylb./cu.ft. 78 94 77 75 76 50 49 (est'd)

TABLE XXVII Ex. Material (wt. %) SG 25 26 27 28 29 30 31 Cement HolcimSt. Gen Type I/II 3.15 31.76 31.71 29.29 24.79 22.80 41.47 42.96 Polymerbeads Copolymer beads 1.06 52.33 54.02 57.53 66.53 68.07 29.41 30.46Microspheres 3M microspheres, S15 0.15 8.38 9.37 Water potable 1 15.9114.28 13.18 8.68 9.12 20.74 17.21

Such exemplary mixes may also include one or more of the disclosedadmixtures and reinforcing materials (e.g. fibers) in amounts consistentwith those disclosed for other embodiments of the invention or in otheramounts. In particular, admixtures may be present in amounts of 0-50 fl.oz./100 lbs. of cementitious materials, such as 0-5, 5-10, 5-15, 15-20,15-25, 20-30, 25-35, 30-40 and 40-50 fl. oz./100 lbs. of cementitiousmaterials. Inclusion thereof may slightly alter the weight percentagesdescribed above; thus those disclosed are approximate.

LWC mixes using such polymer beads may be formed and used to formstructures and objects using the disclosed methods and materials fromthe resulting LWC as already disclosed for mixes or LWC usingmicrospheres elsewhere in this application.

Embodiments of the LWC and LWC mixes include those in which otheraggregates are present in addition to one or more types of LWA. Suchordinary aggregates may include, but are not limited to, sand andgravel. Embodiments also include LWC including LWA both with reinforcingmaterials, such as fiber or steel rod (re-bar) or wire mesh or otherforms of reinforcing, or without reinforcement.

An embodiment of the present invention using such polymer beads (with orwithout sand or gravel or sand & gravel) includes a self-compacting LWCcomposition expected to have a high strength after curing for 3 days, 7days and 28 days, and has a low oven-dried density. The result aftercuring is a lightweight concrete object (such as the structures orobjects disclosed herein), comprising a cured, matrix composite. Thecomposition elements are present in an amount effective to achieve atarget density in said cured composite of not more than about: 125lb./cu.ft., 100 lb./cu.ft., 75 lb./cu.ft., 60 lb./cu.ft., 50 lb./cu.ft.,and 40 lb./cu.ft. or below.

Examples 32-40 Aggregate: SG 0.35 Microspheres, With or Without Sandand/or Coarse Aggregate

Concrete preparation was in accordance with the description for TablesXIII-XIV (above, for Examples 32-33) and XVIII-XIX (above, for Examples34-40), with the addition of Vulcan Sycamore 022CM1601 as a coarseaggregate. All weights for Examples 32-40 are shown below in TableXXVIII (by weight) and Table XXIX (by weight percent). Admixture amountsare fluid ounces per 100 lbs. of cementitious material.

TABLE XXVIII Mix/Ex. E2 E3 F2 F3 F4 F5 F6 G2 G3 SRA SRA SRA SRA SRA SRASRA SRA SRA SG 32 33 34 35 36 37 38 39 40 Material (lb. /yd) CementHolcim 3.15 609 611 611 611 611 611 630 631 611 St. Gen Type I/II FlyAsh Boral Class F 2.49 159 159 159 159 159 159 158 164 159 Silica FumeEuclid 2.29 26 27 27 27 27 27 27 27 EUCON MSA Micro- 3M 0.35 249.7 250205 205 205 205 211.2 77.5 100 spheres micro- spheres, S35 Coarse Vulcan2.69 600 858 1484 1443 Aggregate McCook CM-11 Coarse Vulcan 2.68 855 874918 Aggregate Sycam. 022CM1601 Sand Meyer 2.67 332 325 202 593 577McHenry Fiber Nycon PVA 1.01 6.8 6.8 6.8 6.8 6.8 6.8 6.6 7 6.8 RECS15 8mm Water potable 1 433 425 385 385 365 365 336 263 265 Admixtures(fLoz./ 100 wt CM) De-Air BASF 10 10 10 10 10 Entrainer PS 1390 HRWRABASF 30.9 30.9 30.9 30.9 40.4 30.0 30.9 30.9 Glenium 7500 HRWRA EuclidPSC 30.9 Viscosity Grace V- 8.9 8.9 20.4 8.0 8.0 8.0 8.9 8.9 ModifierMAR Viscosity BASF 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Modifier MasterMatrixVMA 362 Hydration BASF Delvo 2.0 Stabilizer Shrinkage BASF 32.2 48.232.2 32.2 32.2 32.2 40.3 32.2 32.2 Reducing MasterLife SRA 20 Total Wt.(lb.) 1837 1856 2240 2295 2272 2296 2302 3286 3227 W/CM (not incl. 0.550.53 0.48 0.46 0.46 0.46 0.43 0.32 0.33 water in Admixtures) Total(lb./yd) 794 796 796 796 796 796 788 823 796 Cementitious Content Paste(%, incl. air) 49.9 50 47.5 45.9 45.9 46.7 44.5 40.5 38 Content by Vol.Replacement (%) 42.7 42.7 34.8 35.0 35.0 34.2 35.4 13.2 17.1 Volume

TABLE XXIX Mix/Ex. E2 E3 F2 F3 F4 F5 F6 G2 G3 SRA SRA SRA SRA SRA SRASRA SRA SRA Material (lb. /yd) SG 32 33 34 35 36 37 38 39 40 CementHolcim St. Gen 3.15 33.16 32.92 27.27 26.62 26.89 26.61 27.37 19.2018.93 Type I/II Fly Ash Boral Class F 2.49 8.66 8.57 7.10 6.93 7.00 6.936.86 4.99 4.93 Silica Fume Euclid EUCON 2.29 1.42 1.45 1.21 1.18 1.191.18 .82 .84 MSA Microspheres 3M 0.35 13.59 13.47 9.15 8.93 9.02 8.939.17 2.36 3.10 microspheres, S35 Coarse Vulcan McCook 2.69 26.78 37.3945.16 44.71 Aggregate CM-11 Coarse Vulcan Sycam. 2.68 37.63 38.07 39.88Aggregate 022CM1601 Sand Meyer 2.67 18.08 17.51 9.02 18.05 17.88 McHenryFiber Nycon PVA 1.01 .37 .37 .30 .30 .30 .30 .29 .21 .21 RECS15 8 mmWater potable 1 23.57 22.90 17.19 16.78 16.07 15.90 14.60 8.00 8.21

Following this, the fresh concrete properties were measured as describedabove: slump, plastic air content, temperature and plastic density. Themeasured values are provided in Table XXX below.

TABLE XX Mix E2 E3 F2 F3 F4 F5 F6 G2 G3 SRA SRA SRA SRA SRA SRA SRA SRASRA Ex. 32 33 34 35 36 37 38 39 40 Slump (in.) 29 6.75 11.5 21.75 10.524 28.5 19.75 20 Plastic Air Content (%) 8 5.8 7.2 3.5 5.1 5.2 6.2 4 4.8Temp. (F.) 80.1 76.5 76.6 76.1 77.4 78.5 81.8 77.7 77.5 Plastic Density(lb./cu.ft.) 67.6 69 83.5 88.6 74 85.9 77.9 129 123.1

Thereafter, tests were conducted on the physical characteristics of theset concrete, as described above: compressive strength, elastic modulus,tensile strength, modulus of rupture, and oven-dried density. Themeasured values are provided in Table XXXI and Table XXXII(value/density) below.

TABLE XXXI Mix/Ex. E2 E3 F2 F3 F4 F5 F6 G2 G3 Results SRA SRA SRA SRASRA SRA SRA SRA SRA at day 32 33 34 35 36 37 38 39 40 Compressive 3 16801797 1633 1647 2340 1207 4063 3783 1680 Strength (psi) 7 2335 1403 21302673 2693 2677 1887 4973 4443 Elastic Modulus 7 1450 1250 1125 1325 33252750 1450 1250 (kpsi) Oven Dried 56.5 54.5 70 76.5 68.5 75 — 119.5 115.5Density (lb./cu.ft.) Ring test (days) 3.5 1.1 9 3.5

TABLE XXXII Mix/Ex. Results E2 E3 F2 F3 F4 F5 F6 G2 G3 at day SRA SRASRA SRA SRA SRA SRA SRA SRA Strength-to- 32 33 34 35 36 37 38 39 40density Compressive 3 30.8 25.7 21.3 24.0 31.2 — 34.0 32.8 Strength 741.3 25.7 30.4 34.9 39.3 35.7 — 41.6 38.5 (cu.ft./sq.in.) ElasticModulus 7 20.7 16.3 16.4 17.7 — 27.8 23.8 (1000s (cu.ft./sq.in.))

In one embodiment of the invention, precast (or “dry cast”) manufactureof products, including concrete blocks, involves providing extremelylow-slump concrete (almost zero), with a low W/CM ratio (about 0.22 orlower) and a LWA including polymer beads, or polymer beads combined withglass microspheres. Such LWC mixes described herein that do not includecoarse aggregate would be expected to be acceptable for making concreteblocks, with the modifications of removing admixtures and reducing waterto form to extremely low-slump concrete (almost zero), with a low W/CMratio (about 0.22). An admixture could be used as a wetting agent forform removal.

Concrete preparation and block manufacture is in accordance with thedescription accompanying Examples 23-24 and in reference to FIGS. 8A and8B.

Example 41, and exemplary ranges in Examples 42-43 of such a concrete,are shown in Table XXXIII:

TABLE XXXIII Mix/Ex. CMU Rng. Rng. Material (lb./yd) SG 41 42 43 CementHolcim St. Gen Type I/II 3.15 564 400-800 400-800 Fly Ash 2.75 (cement(cement range value range value includes fly includes fly ash) ash)Polymer Beads 0.8-1.4 400  50-500 200-600 350-450 450-550 Microspheres3M microspheres, S15 0.15 114  0-140  0-120  80-125  70-110 Microspheres0.1-0.5  0-100  0-50 Sand Meyer McHenry 2.67 200-450 100-250 Waterpotable 1   see W/CM see W/CM see W/CM W/CM — 0.22 0.15-0.35 0.15-0.35

In one embodiment, a bagging facility prepares the concrete precursormaterials for bagging and delivery and/or sale of bagged dry concrete(blended or mixed). These steps include acquiring bags and concreteprecursor materials including cementitious materials, aggregates, dryadmixtures, and reinforcing materials. This may be done, for example, bypurchase or extraction. A continuous process is used, in which theindividual materials are measured by weight, blended, deposited intobags, which are sealed, and then sold and/or provided for sale. See FIG.4.

Another embodiment of the invention is a concrete mix (and thecorresponding concrete) in which the measured entrained air is very low,including levels of below about 4%, about 3%, about 2%, about 1% andabout 0%, as measured following substantially complete mixing. Commonly,air is allowed to be, or is intentionally, entrained during mixing tovolumetrically expand the concrete mix. This has beneficial effects ofcreating a larger volume of concrete and may improve othercharacteristics such as resistance to cracks and freeze/thaw cycledamage, W/CM ratio, resistance to segregation of components,workability, as well as resistance to de-icing salts, sulfates, andcorrosive water. Adding entrained air, however, also results in a dropin strength of the cured concrete. This may result in the concrete mixhaving to be designed for a higher strength to compensate, resulting inextra material costs (e.g. cement and admixtures). In addition, once aconcrete is mixed to have a design plastic air content, that level ofentrained air can drop as a result of activities associated with the useof the mix, such as pumping (in which increased pressure on the mixforces out entrained air) and delays resulting from transportation orawaiting use of the mix. This results in a loss of design volume thatcan reduce the beneficial effects of the designed levels of entrainedair and reduce profitability. Thus a design mix may have to use anelevated level of entrained air to overcome these concerns. In anembodiment of the invention, a closed-cell and non-absorptive particle,is suitable for displacing a volume within the mix to provide theadvantage of the entrained air without the disadvantages. Alsoadvantageous are particles that are dimensionally (or volumetrically)stable and that substantially resist change of volume under pressure.That displacement eliminates or reduces the need or utility forentrained air to serve that function. As an example, particles such asglass microspheres serve that function, resulting in a similarlyexpanded but stronger concrete. Those particles would be expected toform (as V_(R)) about 5%-25% or more of the concrete mix by volume.Other useful ranges of V_(R) may include about 1%-6%, about 6%-20%,about 6%-15%, and about 8%-12%. In this embodiment, other aggregateswould be likely to be used, including sand and/or coarse aggregates.Low-density microspheres may be preferable, for example those havingS.G. 0.125 or 0.15, where the lower strength of such particles would beof lesser concern, or much higher density microspheres, for examplethose having S.G. of even 0.5 or 0.60 or 0.65, or even polymer beads,where the higher strength of such particles would be of value such as inconcrete having ordinary density, high strength, and which is used ininstances where lightweight concrete is not required butcrack-resistance is desirable (such as in foundations or roads). Suchconcrete can be expected to have compressive strengths ranging upwardfrom 3000 psi, to 4000, 5000, 6000, 7000, 7000, 9000 and 10000 psi andabove, as well as at densities greater than 120 lb./cu.ft. One mixexpected to be appropriate, for example, is one having the generalproportions of that in Example 21. Such concrete mixes could be expectedto be prepared in accordance with the steps set forth in FIGS. 3A-3B,and products or structures made therefrom in accordance with the stepsset forth above.

LWC mixes according to embodiments of the invention may also be used toform concrete roofing tiles, which may take various forms. Concreteroofing tiles are useful as they are hail-resistant and fire-proof, andprovide good insulation. However, a roof composed of ordinary concreteroofing tiles is substantially heavier than the shingle/composition roofthat is usually originally provided, and for which homes are typicallydesigned to support. Concrete roofing tiles formed of LWC according toembodiments of the invention would be lighter and more readilyinstalled, while still providing other advantages. LWC mixes describedherein that do not include coarse aggregate would be expected to beacceptable for making concrete roofing tiles, with the potentialmodification of removing some or all of the admixtures and by reducingwater to form to extremely low-slump concrete (almost zero), with a lowW/CM ratio (about 0.22).

The mixing process steps are, as shown in FIG. 8A and with reference toFIG. 5C, with regard to concrete block manufacturing. One method ofmaking concrete roofing tiles is by supplying the LWC mix to the intakeof an extruding machine, which extrudes an elongated sheet. A cuttingtool cuts the elongated sheet at the appropriate lengths to form theindividual concrete roofing tiles. After this, the concrete roofingtiles are set aside for curing, following which they may be transportedto a construction site or sold for further sale. Curing may includesteam-curing or other processes to develop desirable concreteproperties.

LWC mixes according to embodiments of the invention may also be used toform cement board. Cement board is a combination of cement andreinforcing elements, and are typically formed into 4′×8′ or 3′×5′sheets of ¼″ or ½″ thickness or thicker. They are useful as wallelements where moisture resistance, impact-resistance, and/or strengthare important. Typical reinforcing elements include cellulose fiber orwood chips. The cement material may also be formed between two layers ofa fiberglass mesh or fiberglass mats. Ordinary cement board is, however,relatively heavy and more difficult to cut. Cement board formed of LWCaccording to embodiments of the invention would be lighter and morereadily cut and installed. LWC mixes described herein that do notinclude coarse aggregate would be expected to be acceptable for makingcement board.

The mixing process steps are, as shown in FIG. 8A and with reference toFIG. 5C, with respect to concrete block manufacturing. One method ofmaking cement board is by supplying the LWC mix to the intake of a sheetextruding machine, which extrudes an elongated sheet. A cutting toolcuts the elongated sheet at the appropriate lengths to form theindividual sheets of cement board. Thereafter, the cement board sheetsare set aside for curing, following which they may be transported to aconstruction site or sold for further sale. Curing may includesteam-curing or other processes to develop desirable concreteproperties.

An embodiment of the present invention includes using a LWC compositionor dry mix in applying shotcrete. A shotcrete process is one by which aconcrete mix is conveyed by pressurization through a hose andpneumatically applied to a surface, while simultaneously being compactedduring the application step. Typically, the mix is applied over someform of reinforcements, such as rebar, wire mesh or fibers. There aretwo variants: dry mix or wet mix. The dry mix process includes providingthe dry mix components (e.g. cementious materials, dry admixtures, andLWA) in the respective appropriate ratios, mixing the dry mixcomponents, loading the dry mix components in a storage container, usingpneumatic pressure to convey the dry materials out of that container andvia a hose to a nozzle. At the nozzle, adding and mixing water with thedry materials, while expelling the dry mix and water toward the surface.The wet mix process includes providing the mix components (e.g. water,cementious materials, dry admixtures and LWA) in the respectiveappropriate ratios, mixing the mix components to form a concretecomposition, loading the composition in a storage container, pumping thecomposition out of that container and via a hose to a nozzle. At thenozzle, using pneumatic pressure to expel the composition toward thesurface.

LWC according to embodiments of the invention may be readily cut with anordinary wood saw, without needing a concrete or stone blade. This is sofor those LWC in which all aggregate is LWA as described herein and doesnot include other ordinary aggregates such as sand. Moreover, a personmay easily drive an ordinary nail meant for wood-construction into LWCmade according to embodiments of the invention, without needingspecially-hardened or carbide-tipped nails, and without needing a nailgun or explosive nail driver and/or drill. Moreover, the surface of aLWC according to embodiments of the invention may be paintable(paint-ready), such as for the interior or exterior of a home, or anarchitectural panel. Paint-ready, in this instance, requires that asurface be free of voids.

LWC according to embodiments of the invention is expected to havesubstantially greater insulating properties (higher R-value, lowerthermal conductivity) than ordinary concrete. This is based upon theunderstood relationship between density and conductivity. However, LWCaccording to embodiments of the invention has a much greaterstrength-to-weight (and -density) ratio, and thus can insulate betterfor a given mass and weight.

In this instance, the LWA (specifically in the case of the glassmicrospheres) is much less dense even than water, is the lowest-densitycomponent, and has the natural tendency to float to the top of a mix.This has several undesirable consequences. A primary one is that it cancause uneven properties of the concrete product or structure, resultingin visual deficiencies (i.e. visible aggregate maldistribution). Unevenproperties might mean a portion of the product or structure having anexcessively high concentration of LWA, thus displacing cementitiousmaterials, might be weaker than designed. However, LWC and LWC mixesaccording to embodiments of the invention have highly-homogenous mixproperties, such that the mix density varies by less than 15%, less than10%, and less than 1%. That is, mix design largely prevents the LWA fromsegregating within the mix. This was revealed by pouring a sequence ofabout seven test samples (according to ASTM C192) from a mix over time(about 5-10 minutes), and testing their respective densities (accordingto ASTM C567). In this case, densities measured were extremely similar,differing among themselves by only about 1%. This results in the LWAremaining substantially homogenous and unsegregated upon pouring fromthe mixer and prior to curing, and permits the LWA to be substantiallyevenly distributed within the composition following curing.

An embodiment of the present invention includes a LWC having astrength-to-weight ratio substantially greater than that typically foundin structural LWC, in which the ratio might be (expressed as compressivestrength-to-density) about 2500 psi/90 lb/cu.ft. (about 27.8) up toabout 6000 psi/120 lb/cu.ft. (about 50). Embodiments of the presentinvention include LWC mixes having 28-day compressivestrength-to-density ratios about 81.3 (3310 psi/40.7 lb/cu.ft.), about71.2 (2800 psi/39.3 lb/cu.ft.), about 71.3 (4000 psi/56.1 lb/cu.ft.),about 97.0 (3310 psi/40.7 lb/cu.ft.), about 48.5 (1770 psi/36.5lb/cu.ft.), about 58.1 (7060 psi/121.5 lb/cu.ft.), and about 48.6 (1750psi/36.0 lb/cu.ft.). Embodiments of the present invention include LWCmixes having 7-day compressive strength-to-density ratios of about 29.8(3625 psi/121.5 lb/cu.ft.), 40.5 (1580 psi/39.0 lb/cu.ft.), 31.2 (1890psi/60.5 lb/cu.ft.), 50.6 (2757 psi/54.5 lb/cu.ft.), 62.4 (2427 psi/40.5lb/cu.ft.). This ratio may also be calculated using tensile strengthvalues or elastic modulus or modulus of rupture This ratio is preferablycalculated using strengths or moduli from tests at 28 days or longer,but may also be calculated using tests carried out earlier in the curingprocess. Such ratios calculated using 28-day values are expected to bebetter, as the strength values can be expected to increase with age.

An embodiment of the present invention includes a LWC having a highstrength-replacement-volume factor (“S_(V)”). This value is calculatedby multiplying the compressive or tensile strength by the replacementvolume of the LWA (V_(R), volume percentage displaced by the LWA in thewet mix). Or it may be calculated by multiplying the elastic modulus ormodulus of rupture by V_(R). This is a measure of strength of theconcrete combined with the density-reducing effect reflected by V_(R),in which a higher value is better. In embodiments of the invention,S_(VC) (based upon 28-day compressive strengths) ranges from about 870to about 2000 psi, and includes these values: 1678, 1754, 1422 and 2010psi (mixes in which the only aggregate is a LWA comprising glassmicrospheres) and from about 270 to about 1000 to about 1770 psi, andincludes these values: 268, 1003, 1615, and 1771 psi (mixes in whicheither or both sand and a coarse aggregate were present in addition to aLWA comprising glass microspheres). In embodiments of the invention,S_(VT) (based upon 7-day tensile strengths) ranges from about 90 toabout 115, and includes these values: 89.5, 101.8, 114.5, 94.32 psi (thefirst three being mixes in which the only aggregate is a LWA comprisingglass microspheres). In embodiments of the invention, S_(VT) (based upon28-day tensile strengths) ranges from about 120 to about 180 psi, andincludes these values: 118, 136.2, 156.5, and 180.7 psi (mixes in whichthe only aggregate is a LWA comprising glass microspheres) and fromabout 20 to about 175 psi, and includes these values: 23.8, 112.1,153.5, and 176.7 psi (mixes in which either or both sand and a coarseaggregate were present in addition to a LWA comprising glassmicrospheres). In embodiments of the invention, S_(Vλ) (based upon the28-day elastic modulus) ranges from about 270 to about 460 kpsi, andincludes these values: 273.9, 344.5, 421.6, 405.6, and 458.1 kpsi (mixesin which the only aggregate is a LWA comprising glass microspheres) andfrom about 160 to about 770 kpsi, and includes these values: 158.7,373.8, 462.8, 598.1, and 767.3 kpsi (mixes in which either or both sandand a coarse aggregate were present in addition to a LWA comprisingglass microspheres). In embodiments of the invention, S_(Vλ) (based uponthe 7-day elastic modulus) ranges from about 250 to about 315 kpsi, andincludes these values: 248.5, 254.5, 273.9 and 314.4 kpsi (the firstthree being mixes in which the only aggregate is a LWA comprising glassmicrospheres). This factor is preferably calculated using strengths ormoduli from tests at 28 days or longer, but may also be calculated usingtests carried out earlier in the curing process.

An embodiment of the present invention includes a LWC mix having a lowweight-fraction of aggregate to total dry raw materials (F_(AD)). Thisis a measure of the density-reducing effect of using the embodiments ofthe LWA as described above, and in particular the lower-density glassmicrospheres such as the SG 0.15 microspheres. F_(AD) ranges from about10 to about 75, and includes these values: 30.32, 29.74%, 29.71%,30.01%, 30.06%, 13.95%, 14.37%, and 13.85% (mixes in which the onlyaggregate is a LWA comprising glass microspheres; those falling below15% included SG 0.15 microspheres and less fly ash) as well as 42.08%and 42.06% (each mixes in which sand is included in the aggregate with aLWA comprising glass microspheres). Other mixes with large amounts ofsand or gravel had substantially higher values.

An embodiment of the present invention includes a dry LWC mix having a alow weight-fraction of aggregate to total dry raw materials, andhighly-homogenous mix properties, and which forms LWC having alow-density, low thermal conductivity, high strength-replacement-volumefactor, a high strength-to-weight ratio, and a high strength-to-densityratio. That LWC mix includes embodiments that use an LWA, which LWA mayinclude glass microspheres and/or polymer beads, as described above.

An embodiment of the present invention includes a self-compacting wetLWC mix comprising such a LWA and having such properties.

An embodiment of the present invention includes the process of preparingbatches of components of a LWC mix (wet or dry) comprising such a LWA.

An embodiment of the present invention includes the unmixed componentsof a LWC mix comprising such a LWA.

An embodiment of the present invention includes the process of mixing aLWC mix comprising such a LWA.

An embodiment of the present invention includes the process of providingunmixed components of a LWC mix comprising such a LWA for mixing.

An embodiment of the present invention includes the process of preparingdry LWC mix comprising such a LWA in a continuous process for bagging.

An embodiment of the present invention includes a LWC formed of orcomprising such a LWA having a low-density, low thermal conductivity,high strength-replacement-volume factor, a high strength-to-weightratio, and a high strength-to-density ratio.

An embodiment of the present invention includes manufactured or pre-castproducts comprising a LWC formed of or comprising such a LWA having suchcharacteristics.

The proportions of various components in the tables for Examples 1-24are disclosed by weight, but could also be expressed asweight-fractions, weight-percent, volumes, volume-fractions,volume-percent, or relative ratios (e.g., by weight: 1 part water: 1part cement: 1.2 parts aggregate). Accordingly the disclosed proportionsare scalable for use in larger batches or in a continuous process.

It is to be understood that the invention is not limited in thisapplication to the details of construction and to the arrangements ofthe components set forth in the description or claims or illustrated inthe drawings. The invention is capable of other embodiments and of beingpracticed and carried out in various ways. Also, it is to be understoodthat the phraseology and terminology employed herein are for the purposeof description and should not be regarded as limiting. As such, thoseskilled in the art will appreciate that the conception upon which thisdisclosure is based may readily be utilized as a basis for the designingof other structures, methods, and systems for carrying out the severalpurposes of the present invention. It is important, therefore, that theclaims be regarded as including such equivalent constructions insofar asthey do not depart from the spirit and scope of the present invention.

1. A lightweight concrete composition comprising: one or morecementitious materials; an aggregate mix composed of individualparticles that are substantially volumetrically stable andnon-absorbent; said aggregate mix comprising hollow glass microspheres;and a shrinkage reducer; wherein the lightweight concrete compositionhas a compressive strength after 28 days as measured by ASTM C39 of atleast about 1750 psi.
 2. The lightweight concrete composition of claim1, wherein the shrinkage reducer comprises calcium oxide, calciumsulfo-aluminate, or any combination of any of the foregoing.
 3. Thelightweight concrete composition of claim 1, further comprising an airdetrainer.
 4. The lightweight concrete composition of claim 1, whereinthe concrete composition has an oven-dried density of about 36 to about55 lb/ft³, and a compressive strength after 28 days as measured by ASTMC39 of at least about 2500 psi.
 5. The lightweight concrete compositionof claim 1, wherein said glass microspheres have a specific gravity ofabout 0.15, and said glass microspheres have a 90% survival rate at apressure of about 300 psi.
 6. The lightweight concrete composition ofclaim 1, wherein the concrete composition has a compressivestrength-to-density ratio of about 71.2 to about 97.1, where thecompressive strength is measured in psi according to ASTM C39 after 28days and the density is measured in lb/ft³ according to ASTM C567.
 7. Alightweight concrete composition comprising: one or more cementitiousmaterials; an aggregate mix composed of individual particles that aresubstantially volumetrically stable and non-absorbent; said aggregatemix comprising hollow glass microspheres; air detrainer; and a viscositymodifier; wherein the lightweight concrete composition has a compressivestrength after 28 days as measured by ASTM C39 of at least about 2500psi.
 8. The lightweight concrete composition of claim 7, furthercomprising a shrinkage reducer.
 9. The lightweight concrete compositionof claim 8, wherein the shrinkage reducer comprises calcium oxide,calcium sulfo-aluminate, or any combination of any of the foregoing. 10.The lightweight concrete composition of claim 7, wherein the concretehas a ring test score, as measured by ASTM C1581, of about 10.1 to 16.2.11. The lightweight concrete composition of claim 7, wherein thecompressive strength after 28 days as measured by ASTM C39 of at leastabout 3800 psi.
 12. The lightweight concrete composition of claim 7,wherein the concrete composition has a compressive strength-to-densityratio of about 29.8 to about 62.5, where the compressive strength ismeasured in psi according to ASTM C39 after 7 days and the density ismeasured in lb/ft³ according to ASTM C567.
 13. (canceled)
 14. Thelightweight concrete composition of claim 7, wherein the concretecomposition has (i) a compressive strength-to-density ratio of about48.5 to about 97.1, where the compressive strength is measured in psiaccording to ASTM C39 after 28 days and the density is measured inlb/ft³ according to ASTM C567, and (ii) an oven-dried density of about36 to about 55 lb/ft³.
 15. The lightweight concrete composition of claim7, wherein the concrete composition has an oven-dried density of about36 to about 55 lb/ft³.
 16. The lightweight concrete composition of claim7, wherein the concrete composition has a compressivestrength-to-density ratio of about 40.3 to about 62.5, where thecompressive strength is measured in psi according to ASTM C39 after 7days and the density is measured in lb/ft³ according to ASTM C567. 17.The lightweight concrete composition of claim 7, wherein the concretecomposition has a compressive strength-to-density ratio of about 71.2 toabout 97.1, where the compressive strength is measured in psi accordingto ASTM C39 after 28 days and the density is measured in lb/ft³according to ASTM C567.
 18. The lightweight concrete composition ofclaim 7, wherein the air detrainer is present in an amount of about 6 to10 oz. per 100 lbs. of cementitious materials.
 19. The lightweightconcrete composition of claim 7, wherein the air detrainer is present inan amount of about 8.5 to 14.2 oz. per 100 lbs. of cementitiousmaterials.
 20. A method for preparing a lightweight concrete compositioncomprising the steps of: (a) obtaining a cementitious mixture comprising(i) one or more cementitious materials, (ii) water, (iii) an aggregatemix composed of individual particles that are substantiallyvolumetrically stable and non-absorbent to the mixer, said aggregate mixcomprising hollow glass microspheres, and (iv) a viscosity modifier toinhibit segregation of the glass microspheres within the mixture; (b)reducing the amount of air entrained within the cementitious mixture byadding a air detrainer; and (c) curing the cementitious mixture.
 21. Themethod of claim 20, wherein said hollow glass microspheres remainlargely unsegregated in said cementitious mixture prior to curing. 22.The method of claim 20, wherein step (b) comprises adding a sufficientamount of air detrainer to achieve a plastic air content within thecementitious mixture of between about 2% and 7%.
 23. The method of claim20, wherein, prior to curing, the cementitious mixture has a targetplastic density of not more than about 100 lb/ft³.
 24. The method ofclaim 20, further comprising the step of increasing the resistance ofthe cementitious mixture to cracking during curing by adding a shrinkagereducer to the cementitious material prior to curing.
 25. The method ofclaim 20, wherein said cured lightweight concrete has a compressivestrength after 28 days as measured by ASTM C39 of at least about 2500psi.